23 replies to this topic

[stillentwint17]

Hi,

I was trying to diagnose an oil leak on my 1992 Spec miata. I'm new to working on cars but from what i was reading, i was expecting to switch out the oil pan gasket and the valve cover gasket. Prior to doing so, I added some fluorescence to my engine oil, ran the car for 15 minutes, went under the car with a black light and found the oil was coming out of a "bleed" hole (guessing thats what it is..?) within the bell housing of my transmission. Does anyone know what seal i would need to swtich out in order to fix this. I lost about a 1qt of oil after my last weekend at the track.

I have three track days within the next 2 weeks...Can I continue to drive the car, whilst topping up the oil for the 3 days at track, and fix the seal after or is this a no-go...

[FTodaro]

That is likely the rear main seal or the oil pan seal around the back end of the engine. a common place they leak when they get older.

[davew]

What Frank said.

Requires trans removal.

I would not take to track if you lost a quart last time.

Dave

[Randy Thieme]

+1 on the suggestion not to track it. That much oil down is enough to potentially cause problems for other drivers. (As a part-time corner-worker.)

[stillentwint17]

Thanks for the input guys. Man, this sucks. I was hoping I could just top it off until the track days were over but I have to agree with Randy. I dont want to create a nice little slip and slide for everyone else.

Can anyone remember how long it took to remove your tranny the first time you did it??? I will try to fix this in hopes of making my weekend at Sonoma on the 9th-10th, and ignore Laguna this Sunday. Would you deem that a sufficient amount of time for a noob to compplete this?I will do some research into how to go about this but i was just curious how you would think it would take to remove these seals with limited tooling.

Also, if its the oil pan seal, do i really have to remove the tranny to switch out the seal? I will purchase the parts now and hope to attach it after work.

[Alberto]

Thanks for the input guys. Man, this sucks. I was hoping I could just top it off until the track days were over but I have to agree with Randy. I dont want to create a nice little slip and slide for everyone else.

Can anyone remember how long it took to remove your tranny the first time you did it??? I will try to fix this in hopes of making my weekend at Sonoma on the 9th-10th, and ignore Laguna this Sunday. Would you deem that a sufficient amount of time for a noob to compplete this?I will do some research into how to go about this but i was just curious how you would think it would take to remove these seals with limited tooling.

Also, if its the oil pan seal, do i really have to remove the tranny to switch out the seal? I will purchase the parts now and hope to attach it after work.

As a newbie, It can be a pita since some of the bell housing bolts take some gymnastics to reach. Also, I find mating the trans to the motor to be a challenge. I have only done it once though. Beyond those two things, It isn't particularly hard. The car is easy to work on if you haven't learned that yet. You could probably do it over the course of a day or weekend. If I wasn't down with a nasty flu/cold, I'd offer to help you.

I doubt it's the oil pan.

You could also have a mechanic do it.

How much oil usage are you seeing per session?

[Jaime Florence]

I believe Collin is talking about a single quart of oil in two days (8 sessions) on track plus the 4 hours driving to and from the track. I'm thinking that the amount of oil landing on track would be so insignificant that nobody would ever feel it...until the next rain race that is. The paddock is probably getting most of the dribbles anyway.

Whenvever we've had motors blow up on track it's mostly gone within 6 or 8 laps. I'm betting that it might be better to show up, get your seat time, and then tackle it right away after the event. Since it'll be your first time pulling the transmission you might want to leave yourself a little extra time, not to mention time to order a clutch if it doesn't look very nice.

Just my opinion.

[Randy Thieme]

Granted, that may not be as bad as I thought.

[davew]

My reasoning for saying, fix it or stay home was more mechanical than worrying about oiling the track.

A leaking rear main seal will eventually get on the clutch. Now his parts bill goes up several hundred dollars. What if his 1 quart leak turns into a 2 quart leak and going around a corner he starves the engine for oil and KABOOOM. Now add several thousand.

The tone of the original post tells me he is on a budget. Just a guess ;-) His words "I'm new to working on cars". Maybe the right decision would be to take the money spent on one of his track days and have someone who is NOT new to working on cars repair the leak properly. If the trans has never been out, it will probably be a pain in the.... Sometimes knowing your personal limitations (which will change as you learn) and spending money wisely is the proper plan of action.


Man do I sound old !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Dave

[LarryKing]

My old man is a television repairman, he's got this ultimate set of tools. I can fix it.

[Bench Racer]

Man do I sound old !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Dave

No, experienced and mature.

[stillentwint17]

Thanks for all the responses guys. Much appreicated since i really dont know my ass from my elbow in this situation. I let the car drip yesterday and it accumulated to the very scientifically measured quantity as shown below. This accumulated after 15minutes of running and 24hrs on jack stands. It doesnt seem to drip continuously, but currently thats just speculation. I plan on measuring the oil, driving it for 30 minutes or so, measure again, and probably repeat to see how much oil I'm loosing. If the oil loss is significant i may just bite the bullet and bring it to a shop. If not, I'd like to repair it after the track session. I'd really like to work on the car myself but, i dont know if time is in my favor.

[stillentwint17]

I agree with Jaime. I'll probably need a good few weeks to take out the transmission, get parts, get tools and figure out how to do everything so i would favor doing this after track. I do have a bit of fear of what Dave was talking about. If my motor did go, i wouldnt mind getting a new one but i really dont want to loose out on the track sessions. My motor only pulls like 95hp (pure speculation based off Aaron B.) so i wouldnt mind getting more power. Either way, it would suck to blow an engine.

[LarryKing]

Tool list:
Rechargable 1/2" drive impact gun (highly recommended for quick disassembly/making life easier)
3 - 6" (or longer) 1/2" drive extensions.
1/2" drive impact universal (a must have, in conjunction with the extensions, to get the top bolts of the bellhousing)
A set of metric impact sockets. You will mainly use 12, 14 and 17 mm
A set of regular metric sockets are handy
A long breaker bar for when your impact ain't got enough grunt.
1/2" drive torque wrench
Clutch alignment tool - I'm pretty sure I bought mine from Mazda.

I know I'm forgetting stuff but that's a start.

Step 1 - unhook the battery
Step 2 - drain transmission

Don't forget to RTV the flywheel bolts when reassembling or else you'll still have a leak.

WAG, but I'd say your seal is leaking at a slower rate than some are assuming. Also, you "should" be able to R&R a transmission on a weekend afternoon assuming you have all your tools and parts ready to go.

[Anthony Ralston]

It's not that hard. My friends and I swapped out a motor from one Miata into another in a weekend. It was our first motor swap.
Just dropping the tranny is much easier; hardest part is realigning everything.

Here is an awesome picture walkthrough. http://www.miata.net...utch/index.html Just ignore the part numbers. I'm not sure which year Miata he has.

You will need 3-4 extensions and a universal joint to get the transmission bolts off.

I would NOT run a track event in its current state. The oil can screw up the clutch. (been there, done that...)

[Keith Novak]

It really isn't that hard but for your first time, budget twice as much time as everyone is telling you. If someone is showing you how to do it, that's one thing. If you follow a manual it may tell you a far more complicated way to go about it. Depending on who worked on your car before, they may have already dealt with several really annoying bits like unnecessary brackets and P-clamps to hold wire bundles in places you can turn the wrench 1/32 of a rotation, overtightened bolts, yada and more yada.

Once you've been taught the easier way or fumbled through the experience, learned where you can and can't access the bolts with a wrench from various directions, it's annoying but not terrible. If you're on a budget, I'd budget the time and figure it out rather than pay a shop way too much to do it. Often they're charging by the hour and expecting to deal with those annoying P-clamps and stuck bolts too. Plus, after a while you will probably have one fail at the track and not want to quit your weekend.

I'd also NOT recommend driving it on the track with a known leaky anything. Even if it doesn't blow, or slick down the track a ton, you're driving around with the fact you have a leaky something that could get ugly very quickly in the back of your head and that in your head is not conducive to learning to driving fast. Been there...more than once and I'll trade reliability and a clear head over seat time and changing band-aids between sessions any day.

[LarryKing]

FWIW - brake clean will un-screw an oily clutch disk, and, if I've already dropped the trans and don't know the age of the clutch/PP, I'm going to replace it anyway.

[davew]

FWIW - brake clean will un-screw an oily clutch disk, and, if I've already dropped the trans and don't know the age of the clutch/PP, I'm going to replace it anyway.

If it is a ceramic style race disc I agree. If a stock type disc material, once oil soaked they will not clean up completely.

Assuming the trans has never been out of thr, it will most likely need a clutch also.

Dave

[Todd Tagget]

Get your track days in.. in the meantime shop around for a spare tranny (Ron ?? Ron ??)
Dude you live in N, Cal,, SOMEBODY will be willing to help you for an afternoon..
Personally, if you've never done a partial and may have a rear seal to replace, I'd a lot the time and plan on pulling the whole motor/tran there's probably a lot of "while I"m in there" stuff to be done as well..

[stillentwint17]

Thanks so much for the great input Anthony, Keith and Moose. I've compiled your input into a document that I will create a process instruction of how to switch out my tranny.

An update on the oil leak. I ran the car for 15minutes yesterday, then drove it on the freeway for 20 minutes, drove it up Skyline (hard) for about 40 mins, then drove it for another 20 mins on the freeway. I measured the oil before and after the drive. The image on the left is before, the image on the right is after. It was a great result, in my opinion as it looked like no oil leaked throughout the drive. Also, no oil has leaked since last night. None whatsoever over the 24hrs.

Obviosuly, there is a leak somewhere, but i dont think i will address it until after Sonoma, this feb. The car sat, without been driven since the last track day last season (Nov...i think?). I'm assuming the oil trickled through the seal into the tranny and collected over the last 2-3months. When i raised the car the other day, i tipped the car high enough for the oil to leak out of the tranny. This doesnt explain the 1qt i lost, just the oil that i showed in the image above. I'm guessing my car burns a good bit of oil and that with a combination of me not filling it properly would explain the qt. I'm not exactly sure. Its either that or track days exasperated the leak and it leaked over the two nights of track... Either way, i plan on switching the oil out, and I'll complete the same test. I also plan on taking the tranny out after track so i really appreciate all your input. Anyone else going to Sonoma next weekend?


Well...crap....the fact that the flurescence came out through my tranny within 15mins nulls my comments above...fml.. Is that flurescense stuff prone to expanding gaskets to the point where its easier to seep out...