Drew_K

My 92 C2 isn't getting oil to the front oil cooler. I was going to try changing out the relay, but, assuming I have to replace the thermostat, is it a pretty difficult job?

I know the thermostat is located in the passenger side rear wheel well. From what I've read, it's pretty hard to loosen the oil tube connections. Other than that, is there a real trick to it? Seems like it should be pretty straight forward - unsrew old piece, screw in new piece. I'm trying to figure out whether I can do this myself or whether I should take it to my mechanic.

Thanks in advance for any guidance,
Drew

axl911

It's not that difficult.

You will need a 36mm and 32mm open end wrench. Get thermostat, 2 rubber hoses goint to T-stat, the 2 rubber hoses going to the oil tank, and 4 hose clamps (might as well as change them out while you're in there). I got everything at Sunset except for the wrenches for ~$330.

>>>MOST IMPORTANT STEP<<<
Remove the side rocker. 3 days before, spray the hard line connection joint with a lubrican spray like PB Blaster or something. WD40 is useless. Let sit for couple hours, spray liberally again. Do this about 5 times.

Drain oil tank. Then use the 32mm and 36mm wrench to undo the oil hard line. Use both wrenches otherwise, you'll put leverage on the housing and will twist it. Then like you said, unscrew old piece and screw in new one. Real easy. Remember which rubber hose goes where and how it's oriented. Space is tight but doable. I replaced mine in 2 hours.

Put oil back into tank. I ended up needing 6 quarts since I drained the tank and cooler pretty well.

On 91 or later model, they change the thermostat to one where you can just change out the thermostat element. My 92 doesn't have this so I have to get the entire thermostat. I wouldn't go used parts here since the thermostat is IMPORTANT.

BTW, I bought the oil line wrench set from Pelicans. The 36mm fits, the 32mm doesn't fit. Luckily, I have a Craftsman 32mm that fit well.

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anthony

Jeff Midili

I've replaced mine as well and agree with all the excellent advise Tony has provided. A couple of extra tidbits:

1) pay very close attention to the torque setting on the oil drain plug, the housing is aluminum and can crack if you over-torque it.

2) this may only apply to the 1991MY but when I replaced my housing the one I got, witth the exact same part number, was different. The soft oil line connectors were of a slightly larger diameter and one was at a slightly different angle to the housing body. It still fits, but if it is different you might have to trim the soft hoses to get them to fit. I had to do this in order to get the rocker panel back on correctly.

Oh, and I've been using Kroil, with excellent results, to loosen up parts.

Regards,

Jeff

Drew_K

Thanks for the great advice guys. This sounds do-able,m so I'll be ordering the parts tomorrow as well as 32mm and 36mm wrenches.

Just out of curiosity, how long did the job take?

axl911

It took me 3 hours, but I work slow, took frequent breaks to enjoy the view of how things are put together.

It's a simple job. Try to break the hard line connections first. If you can't, then it's just a simple matter of pouring back the oil and drive to your favorite mechanics. He would thank you for already removing the rocker panel for him.

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anthony

GMS

You do't need to replace the whole assembly. The actual thermostat is available seperately avoiding removing the casting. You need the thermostat, cover plate, circlip and o-ring. It's a good idea to get the clips for the end piece of the rocker panel that has to come off for access.

Jeff Midili

GMS is correct in theory, and I would pursue the option of replacing just the thermostat first. In my case, I could not remove the cover plate from the housing. I tried all kinds of things including heat, which is a little dicey with aluminum. This was in fact the first DIY I tried on my Porsche, but I'm still not convinced I could have gotten the plate off today. It was really on there!

Finally I just had to replace the whole thing. The money spent on the housing was well worth the wasted hours trying to pull the plate. I think I got my housing at DCAutomotive, a rennlist sponser, for $250.

I think there are two approaches to this option:

1) try and remove the plate. If you can then just order the thermostat, if you can not then order the housing, which comes with a thermostat.

2) Order the housing and see if you can return it minus the cost of a new thermostat. Then if you don't need the housing you can return, but you'll have it there to finish the job in one day if need be.

The issue is you have to empty the oil as a first step, so you if you empty the oil but then can't get plate off then you will have to refill if you want to drive the car but don't have the housing to replace....

All in all, once I committed to replacing the housing it took about 3 hours, but I too took my time and had to deal with trimming the soft oil lines.

The correct wrenches make the job easy and just take care when screwing the hard lines back on to your new aluminum housing.

Regards,
Jeff

Bob Krantz

Ditto to both of Jeff's posts: on my 89 the replacement thermostat was slightly different, and required updated hoses (something my local dealer parts gal did not catch, and we had to swap new incorrect hoses for the right ones). I also tried to remove the side cap, without luck. Even once the entire unit was on the work bench, it would not budge. A little corrosion goes a long way. Which gets me back to thinking about the design: the thermostat, with its different (and thus galvanic corrosion-prone metals) sits at a low point, since it is also the tank drain. When water separates from the oil, guess where that goes? When I used to live in cold climate, I would periodically crack open the drain plug enough for capillary action along the threads to drain a small amount of presumably nasty, acidic water. Just the thing to rot my new thermostat.
Bob K
89 C4

Drew_K

UPDATE
----------------------------------------
I was able to replace just the thermostat element rather than the entire housing. I took the car for a long drive and I'm getting oil flow to the front again (passenger side front fender is very warm). Thanks for all of the advice! At first, I was going to order the entire housing, which would have been a much larger job. THANKS GMS!!! I do understand that in some cases the thermostat housing cannot be opened so the only choice is to replace the entire housing.

For future reference, here's a short writeup of what I did. Hopefully this will help someone in the future.

1. Order the thermostat element, an o-ring, and snap ring. It's about $100. Also order a few extra plastic clips that hold on the side rocker. I broke one of mine during removal.

2. Put the car on a lift or jackstands. Drain the oil from the passenger side drain plug.

3. The thermostat housing is just in front of the passenger side oil drain plug. Remove the passenger side rocker panel. To do this, remove all of the screws and plastic nuts holding the panel on. Some most are underneath the car. There's one in the front wheel well.

There's apparently a nut that has to be removed that can only be accessed by removeing the front wheel well liner. I didn't know this and broke that particular tab off in a way that isn't fixable. Doesn't seem to be a big deal b/c there are many tabs to hold the rocker in place.

Once you have all of the nuts and screws removed, there are about 6 plastic tabs holding in the top edge of the rocker. Start from one end and pull on the rocker near each tab to remove it. You may break a few tabs in the process, which is why it's good to have extras. Broken tabs are easily replaceable, except for the one I mentioned in the prior paragraph.

4. Once the rocker is removed, you can see the thermostat housing. You'll see a snap ring on the side. Remove the snap ring, which will probably require a snap ring tool. I managed with some surgical tongs but it wasn't easy. I would definitely recommend getting a snap ring tool if you don't have one.

5. To remove the cover, I used a small screw driver and pried a little on it. It popped right out. Hopefully yours will do the same. If you can't get it out, then you're stuck with having to replace the entire thermostat housing.

6. Assuming you get the cover off, pull out the old thermostat element and its spring. Make a note of how these pieces are oriented so that you put the new pieces in the same way. Remove the old rubber o-ring and replace with a new one. Put the new thermostat element and spring in; the spring goes in first.

7. I struggled with the putting the cover back on b/c you have to apply a lot of force to push it back far enough to reinstall the snap ring. Then it finally dawned on me to use a vice. Reinstalling the cover would have been very difficult without a vice, so I suggest you get one for this job. Put one end of the vice on the back side of the housing and the other end on the cover. Clamp it down until the cover is fully depressed within the thermostat housing. Reistall the snap ring. Then reinstall the rocker.

Also, you may as well do an oil change now because you've already removed most of the oil from the car.

Hope this helps someone.
Drew
92 C2

JoeW

Very good write-up, Drew. I'm glad it worked.

What's a "snap-ring tool"? J

wicks

Am I really going to need a 36mm wrench? They're like 2 feet long. Haha. Using the adjustables on the oil cooler oil line fittings, which is fine there - is there limited space once I dig into the thermostat end of the lines?

Goughary

Space is tight.

You need a 32 and a 36 mm

You can use crows feet or you can buy some cheep box ends and cut a slot to fit over the pipes

Or- just buy the sir tools wrenches...

The job isn't difficult- cracking those nuts if they have been on there for 30 yrs is a pain.

wicks

Thread above says 32mm and 36mm ... ?

John McM

32mm and 36mm for the rear most fitting at least. If both are wrenches then you can put them both together on the respective nuts and use your hand squeeze to undo and do them up.

Goughary

Sorry that was a typo. 32 and 36 is correct...