39 replies to this topic

[Kyle Freiheit]

I was having cooling issues before my last race and could not figure it out because I have never had cooling issues with my current setup(fat koyo). Before the last race I flushed the entire system untill I was getting nothing but clear water coming out. Well, this morning I tested the votage of the coolant/water in the radiator in it was .7-.8V. That is alot. When I drained it, it was very rusty colored. I am going to be pulling the motor for a refresh this winter but decided I should flush the system again and attempt to neutralize the electrolysis because it is going to be a month before a pull the motor.

Some guys say to run a ground strap to the radiator, some don't. Almost every place I read they say to run a anode(sacrificial metal) dangling from the radiator cap. I am think of running a chunk of lead.

Fun.

Kyle

[SaulSpeedwell]

I was having cooling issues before my last race and could not figure it out because I have never had cooling issues with my current setup(fat koyo). Before the last race I flushed the entire system untill I was getting nothing but clear water coming out. Well, this morning I tested the votage of the coolant/water in the radiator in it was .7-.8V. That is alot. When I drained it, it was very rusty colored. I am going to be pulling the motor for a refresh this winter but decided I should flush the system again and attempt to neutralize the electrolysis because it is going to be a month before a pull the motor.

Some guys say to run a ground strap to the radiator, some don't. Almost every place I read they say to run a anode(sacrificial metal) dangling from the radiator cap. I am think of running a chunk of lead.

Fun.

Kyle

1. I went through the same quandary. When I grounded mine, the potential went down - and thus, I have to believe fewer electrons are leaving my car's engine/radiator/heater core to otherwise become one with the H20. That can only be a good thing.

2. Distilled water won't cause scale as readily, but it will potentially steal more electrons. Using fresh fluid all the time isn't necessarily wise. I do a lot of draining, filtering, and recycling, adding only the additional water and coolant necessary to keep enough freeze protection. I always get highest potential with fresh coolant.

3. The sacrifical metal normally used by the marine geeks is zinc.

I always heard rumors of mystical water pump lubricant that was separate from "coolant" - but I simply chose to put everyone's lives in danger by running about 15% antifreeze, and all my rust and sediment issues went away.

Sidebar: I have a 1992 daily driver still on original hoses, belts, radiator, H20 pump, and most everything else, with about 80K miles. It has had one coolant change in its life, failrly recently, and I was a little worried about doing it. If BMW/M-B/Porsche could figure out how to make any part of their cars as reliable as 99% of NA MIata parts, what a wonderful world it would be . . .

[Kyle Freiheit]

RobertFenderSpeedwell,
Thats the conclusion I have come to as well. I tested for faulty grounds and isolated a few variables to attempt to find if there was some stray voltage from the battery... nope. Do you think it would be better to ground the radiator, ground the radiator cap with a zinc anode attached, or both? Alsp, tap water vs distilled hasn't made much of difference in my initial voltage testing yet. I am about to add coolant for the winter right now.

Kyle

EDIT: Did some hot flushs until the water came out clear. Then added antifreeze for winter. Still got .6V in the coolant. Added a ground wire to the radiator, no change.

[Michael Cola]

What does that foam smell like, taste like? Is the foam whatever is causing it, your Napa Kool?

Smells like NapaKool. I'm not brave enough to taste it. lol

The ultimate practical joke. Someone is sneaking out to the garage and dropping half an alka seltzer in your radiator. Funny

Haha. No one else is around except me. Unless my wife is really trying to mess with me? I doubt she'd even think of it. ;-)

At risk of being flamed to death by the safeniks, I always used about 15% antifreeze in my car, after having a host of obvious contamination (e.g. red "rust") crop up in the cooling system after only a few weeks of running pure distilled water and Redline Water Wetter. During the off-season, I would drain the system and put a lot more antifreeze in.

This makes sense to me. I've read about people doing this and it seems relatively harmless since it'd be diluted so much by the water. I'd contemplate doing this if I still had issues with foaming with only water wetter / NapaKool.

================================

So I did some checks on Friday. Checked with a multimeter and had very very little resistance between the engine and ground and between the radiator and ground. The radiator doesn't have ground straps on it, but it seems to make a connection just fine through the mounts. (Writing this out now, I realize that I didn't look at voltage and went right on to other things, which was stupid of me. I'll check when i get home tonight for the hale of it, but I honestly don't think it will matter....read on...)

I decided to flush the coolant and replaced it with 100% distilled water. I left the drained coolant (NapaKool + distilled water) in a bucket all weekend and it behaved like water should.... No foaming, no bubbling, no paranormal activity. It didn't bubble at all when it was drained into the bucket. It just looked like water and it was pretty clear.

I started up the car and let it run up to temp to 'burp' the coolant system. I checked all the hoses when things were warming up, and everything seemed to be in place. I wiggled them around but nothing budged and nothing leaked. Everything was fine till it got to temp and the thermostat opened. Once it opened, there was some steam that came to the surface and a ton of water got pushed out of the system (much more than is normal from the burping process). I refilled it once the level went back down and became stable, and then I closed the radiator cap. There was no foaming at all before I closed the cap, even after the thermostat opened, which makes me think that something in the NapaKool was the source of the foaming.

About 30 seconds later, the cap opened (its a 4-month old cap - shouldn't be any issues with it) and it started belching air out into the overflow tank. A minute later, it was a constant stream of air blowing out of the cap into the overflow tank (like sticking an air hose into the tank).

Great.........

My only conclusion....blown head gasket. I didn't verify my suspicion with a block test kit from Autozone yet, but I guess I could do that tonight. It doesn't hurt to confirm, but I'm 98% sure that its the HG.

I checked the water after the engine cooled off and there was no foaming or bubbling. Seems like Keith Novak and SaulSpeedwell were right to suspect the leaky gasket. Needless to say, I didn't make it to the track, which sucks. I'm just glad I caught it before starting the 3-hr drive to CMP...that could have been bad.

---------------------------

So now I'm wondering...just replace the HG (with machining as necessary and head rebuild)? Refresh the whole engine (rings, bearings, oil pump)? Or replace it for another engine for cheap?

I'm leaning towards just doing the HG, since the engine still ran strong and had good oil pressure. Bottom end has ~120k on it since its last rebuild. I think I'll tear into it and see how everything looks when i get in there...

[Randy Thieme]

I can't answer your questions on the engine rebuild but I can comment on the radiator. The radiator mounts to the support with rubber bushings. If the bushings are intact the radiator should be isolated. Over time the bushings can dry and crack allowing metal-to-metal contact. Off hand I don't have the part #. They're a little hard to find on the http://www.mazdaspeeddevelopment.com/ website. Instead of the usual parts look-up entering your car year and model, etc. use their collision guides instead. The bushings are listed there.

[Michael Cola]

I can't answer your questions on the engine rebuild but I can comment on the radiator. The radiator mounts to the support with rubber bushings. If the bushings are intact the radiator should be isolated. Over time the bushings can dry and crack allowing metal-to-metal contact. Off hand I don't have the part #. They're a little hard to find on the http://www.mazdaspeeddevelopment.com/ website. Instead of the usual parts look-up entering your car year and model, etc. use their collision guides instead. The bushings are listed there.

Interesting. My Mishimoto radiator actually doesn't have those rubber bushings at all. It just has metal posts that fit into the u-channels at the bottom. Seems like it fits nicely, so its possible that the lower u-channels were modified to fit snugly. It also has two metal tabs that bolt through to the upper mounts - this is where I assume that the direct metal to metal contact is.

[DrDomm]

In your professional business, if you looked into one of your patients _ _ _ _ _ and viewed foam, would the foam be normal?

Most women are a little more particular about their parts than we are (about Miata parts). Thankfully.

[Randy Thieme]

Interesting. My Mishimoto radiator actually doesn't have those rubber bushings at all. It just has metal posts that fit into the u-channels at the bottom. Seems like it fits nicely, so its possible that the lower u-channels were modified to fit snugly. It also has two metal tabs that bolt through to the upper mounts - this is where I assume that the direct metal to metal contact is.

Right, I was assuming whichever aftermarket is being used mounted the same as the stock radiator.

[Michael Cola]

Sure sounds like galvanic corrosion. It's a phenonema that occurs when you have two significantly dissimilar (or as metallurgists refer to as being more and less "noble") metals in contact (or in close proximity) while in an electrically conductive fluid. Since distilled water isn't electrically conductive, and you used the same inhibitor previously that doesn't really sound like your issue. The other option is a weird electrical problem that's electrifying some part of the car and not another. Have you physically disconnected the batery cables top rule that option out?
Rick
P.S. 2% leak down on an unrebuilt 140K motor sounds almost too good to be true.

Qik Nip, Your note here bothered me. I knew the leakdown numbers were all close, but I was going off my really poor memory. I found my actual numbers from my leakdown test performed on 10-30-2012 (~2 weeks ago - and the car was only driven one day for 15 miles, between then and now).
My 2% estimation was wrong.
They were:
Cylinder #1 = 97% (3% leakdown)
Cylinder #2 = 98-99% (1-2% leakdown)
Cylinder #3 = 96-97% (3-4% leakdown)
Cylinder #4 = 97% (3% leakdown)




Ok...this is starting to drive me crazy.

Head Gasket Testing:
So I rented the block test kit from Autozone. I read the instructions multiple times, cleaned out the tester as it suggests with new clean distilled water, and removed enough coolant from the system to keep it from the tester. I then performed did the test multiple times, cleaning the tester in between each trial:
Test #1) Cold (idling, warming up) = Pass (no change in fluid color, which means no exhaust gas is present in coolant)
Test #2) Just as the thermostat opened = Pass (no exhaust gas is present in coolant)
Test #3) Car was at operating temp and had been revved up a bunch. = Pass (no exhaust gas is present in coolant)
Test #4) Car had been running for 10 minutes warm = Pass (no exhaust gas is present in coolant)

Really?!

I tested the fluid using the method described in the instructions. This involved cleaning everything out and putting fresh fluid into the tester. Then you exhale towards the tester while pulling in air through the tester. The fluid turned yellow as it is supposed to.

One other thing I noticed this time...when I shut off the engine after the test, there was still just a little bit of foaming, (maybe 1/3 of what was shown in the "JustOpened" picture I had attached earlier, that had little foaming to begin with). The water was still clear, but i could see and hear the bubbling from the radiator core tubes. This is still in 100% distilled water.

Ok then....so maybe I was completely wrong and it really isn't the head gasket...back to the electrolysis testing, I guess?


Electrolysis Testing:
I pulled out the multimeter again and took a bunch of measurements between the following locations (Ranges given for times when voltage varied over time):

Coolant to Radiator, Engine On = ~0.69 - 0.75V
Coolant to Chassis, Engine On = ~0.69 - 0.75V

Coolant to Radiator, Engine Off = ~0.40 - 0.57V
Coolant to Chassis, Engine Off = ~0.40 - 0.57V
Coolant to Negative Battery Terminal, Engine off = ~0.40 - 0.57V

Radiator to Chassis, Engine off = 0.0V
Radiator to Negative Battery Terminal, Engine off = 0.0V
Radiator to Engine block, Engine Off = 0.0V

Negative Battery Terminal to Engine Block, engine off = ~1.5 ohms
Negative Battery Terminal to radiator, engine off = ~1.5 ohms

Then I disconnected the battery....

Coolant to Radiator, engine off = ~0.40 - 0.57V
Radiator to Chassis, Engine off = 0.0V
(No change!)

So, according to the information
here: http://www.sancarlos...lectrolysis.htm
and here: http://www.voltagedrop.biz/
and here: http://www.awrracing...lectrolysis.pdf
and here: http://www.birdsradi...lectrolysis.nxg
and here: http://www.carolinar...lectrolysis.htm

Since removing the battery from the equation ruled out issues with grounding, It seems like I have "Type B" electrolysis and have an issue with the sediment in the block itself. Time for a serious flush I guess....?

Sounds like I also should be looking to insulate the radiator from the chassis, by using the rubber bushings that RandyT suggested (or some electrical tape or rubber hose?).

Some of the sites suggest the use of the sacrificial annode, others say its a silly idea. I'm not sure.



Any further thoughts from you all? I still find it hard to believe that the electrolysis can produce that much "air" into the system...

Thanks,
-Mike

[Bench Racer]

Call the manufacture of NAPA Kool explain the situation.

[Keith Novak]

This is turning into quite the science project. Be careful about attributing effects to causes:

The block test kit can’t definitively rule out a head gasket leak. It can only confirm combustion gasses. A result that isn’t positive can mean a) you don’t have a leak or the test isn’t detecting the leak. I’ve had them negative before with a small leak. It later showed positive and there was a leak. I can’t say why it didn’t the 1^st time for sure but I t didn't and it was wrong.

Electrolysis: Pushing a current, even a low one through the system will definitely case electrolysis and that can eat radiators. That’s not the question though. The question is whether electrolysis is creating a significant amount of gasses in your system. If it’s passive due to dissimilar materials, that’s a pretty slow process unless you put an acid in there. (Note: Don’t flush the system with Draino) If there’s a stronger current being pushed through there, I wouldn’t rule it out but I’m still skeptical that it’s generating a lot of gasses. I tried measuring current through my radiator in the past but I concluded my results were junk. BTW…with the engine running you can disconnect the battery and the system will run off the alternator.

Other options for the bubbling? Well there is definitely something that makes the bubbles foamy. It’s probably the Napacool stuff. Just draining it won’t get it all out. You’d really need to flush it. I’ve flushed my system multiple times and it takes a few flushes to get the water looking cleanish. You have less foam than before so that would make sense. The bubbling going on in the radiator though could be cavitation. Does your track car have a stock WP pulley on it or a smaller one that will cause it to turn faster? There’s also the radiator. I’ve never used a Mishimoto but it could be that the way it’s constructed is forcing the coolant to rapidly change pressure in places generating bubbles. Is there another radiator you could try?

FYI- I isolate my radiator with a combination of the rubber bushings on the lower mounting points (I think they came off a stock radiator) and I put rubber washers on both sides of the aluminum mounting points on top. It’s not fool proof but the only leaks I’ve had are the result of FOD.

[Kyle Freiheit]

Mike,
My testing was the same as yours. I think that there is just a bunch of scale/rust in the block and radiator now. I am probably just going to have the block cleaned up at the machine shop and replace the radiator, so I should theorhetically be starting from scratch next season.

I am considering running a zinc bar as a sacrificial anode. As the bar dissolves it should attach to the iron block(cathode) and over time should stop the rusting of the block(i think). Might take awhile but in the mean time it will stop our radiators/heads/heater core from being attacked.

FYI- I did try the Prestone Flush and it really didn't do much, I was afraid to leave it in to long. Maybe longer would be better? I have also been reading about guys using vinegar/water as a flush and although it sounds like snake oil, the science says it should work.

Kyle

[Randy Thieme]

The bubbling going on in the radiator though could be cavitation...

Now there's an enteresting possibility although I've never heard of it. Almost like air gets mixed in under pressure and then opening the radiator cap is like opening a can of soda. Caused by cavitation? Or could the pump somehow be drawing air in and mixing it with the water?

Michael, Have you measured the cooling system pressure while the engine is running? Or done a cooling system pressure test with the engine off?

[Keith Novak]

Now there's an enteresting possibility although I've never heard of it. Almost like air gets mixed in under pressure and then opening the radiator cap is like opening a can of soda. Caused by cavitation? Or could the pump somehow be drawing air in and mixing it with the water?

There's already air dissolved in water. That's how fish breathe. The best examples I can think of are boat propellers and dragging a stick/fishing rod tip quickly through water. In both cases you see bubbles form off the prop or stick. They're not dragging air down into the water. The rapid pressurization and expansion causes "holes" in the water. Forcing water through a tight spot will do it too. It compresses and rapidly expands as it's forced through a nozzle.

[SaulSpeedwell]

RobertFenderSpeedwell,
Thats the conclusion I have come to as well. I tested for faulty grounds and isolated a few variables to attempt to find if there was some stray voltage from the battery... nope. Do you think it would be better to ground the radiator, ground the radiator cap with a zinc anode attached, or both? Alsp, tap water vs distilled hasn't made much of difference in my initial voltage testing yet. I am about to add coolant for the winter right now.

Kyle

EDIT: Did some hot flushs until the water came out clear. Then added antifreeze for winter. Still got .6V in the coolant. Added a ground wire to the radiator, no change.

He11, I don't know. I have an MSEE, but that just makes me dangerously arrogant, not infallible, much less smart or correct.

I'd be curious if you get a different reading with the battery disconn'd. In other words, I'm curious if the radiator/coolant is being a "battery" or something more passive. On my "problem car" (not a Miata), the ground helped because I was only getting a potential with the battery connected - I think that means the engine was becoming a "resistor" because a ground was wonky, but I don't know why the potential was different in the coolant than on the block, etc.

Worse - despite almost failing undergrad Organic Chemistry, this "feels" chemical in nature to me - not electrical.

If it was my car, I'd put in distilled water, get it hot, let it cool, drain it, fill it with distilled and 15% coolant and water wetter, and wait for a failure that will probably never come. On engine changes and such, I would drain, "filter", and reuse that mixture for a very long time. Repurpose all this effort into getting faster, getting thinner, getting richer, or getting happier.

You are probably chasing a ghost that has nothing to do with laptimes or how many $4 pine and Lucite trophies you rack up. But, sometimes this stuff is mental masturbation, and I understand if you want to keep chasing it. Youv'e got me hooked too now.

[SaulSpeedwell]

FWIW: 1992 daily driver, 80K miles, nothing changed in coolant system except coolant drain and refill in 2011:

VDC from coolant in radiator neck to radiator shell (Aluminum): ~0.130V
VDC from coolant in radiator neck to valve cover: ~0.200V
VDC from coolant to radiator neck to shock tower bolt: ~0.200V

Now the mindfork (for me, anyway): VDC with both leads in the coolant in the radiator neck, ~2 cm from each other: 0.120V

VDC with leads stuck in old plastic bucket of coolant, ~2cm apart: 0.60VDC
VDC with leads stuck in old plastic bucket of coolant, ~20cm apart: 0.60VDC

What does this tell us? That we are dumb and chasing "noise", probably

[Keith Novak]

Now the mindfork (for me, anyway): VDC with both leads in the coolant in the radiator neck, ~2 cm from each other: 0.120V

VDC with leads stuck in old plastic bucket of coolant, ~2cm apart: 0.60VDC
VDC with leads stuck in old plastic bucket of coolant, ~20cm apart: 0.60VDC

What does this tell us? That we are dumb and chasing "noise", probably

That's precisely why I quit my bucket and multimeter experiments to find the least conductive coolant additive.

[Kyle Freiheit]

I feel like I should be surprised, but nothing surprises me with this crap anymore. I am a little disappointed that I didn't think to test new vs old(water/coolant/water wetter) combos in a bucket... thanks for doing it for me.

Kyle

[Alberto]

fwiw, it took 7 flush and fill cycles using new distilled water each time for me to get clean water out of my unrebuilt street engine and used radiator. I had tried both flavors of the prestone coolant system cleaner during/before this and it didn't make a change that I could notice visually.

Since you are testing, you may want to 'rent' a coolant system pressure tester to test for leaks in your coolant system. I understand that if the motor has a leaking head gasket, the coolant will be forced out the leaking area. I know it works for leaking coolant hoses and tired hose clamps.

[Michael Cola]

So, I realize that it's been well over a year since the last post in this topic, but I wanted to close it out for record keeping sake and report what happened.

 

After my last post and contemplating the problem for a while, I still couldn't figure out what was going on. I was still suspicious of the Head gasket, so I decided to just pull the head, rebuild it with new seals, and replace the head gasket while I'm at it. I was going to have to do this at some point anyways, since the valve stem seals were leaking and was causing me to burn oil during high engine vacuum (off-throttle decel). Kill two birds with one stone (hopefully) was my thought.

 

I had the head rebuild by Mike Rossini at Rossini Racing in Winston Salem and he did a great job with it. I rebuilt the top end with all new gaskets and installed all new coolant/vacuum hoses from Mazda. I used the same radiator, radiator cap, water pump

 

After rebuilding the engine, the symptoms I had been experiencing were gone. No more bubbling, no more over-pressurizing the coolant system, no more burning oil, no more problems. It's been running for the last year and done a couple track weekends without any issues. I'm honestly not sure what it was that fixed it....I think it was the head gasket that was just slightly leaking, but I can't confirm it for sure. The gasket wasn't obviously damaged anywhere, but had gone over 140k miles and taken two drivers through HPDE/Race school. Who knows.

 

I'm just glad it's fixed and that my next track weekend is coming up in May! :-)

 

Good luck to anyone else that finds this thread and are having similar issues.