Catera coolant leak

ewill3rd · #1 (**permalink**) 01-01-06, 11:58 AM

I heard someone talking about coolant leaking from a Catera at the rear of the engine but the water valve had already been replaced. I thought it didn't belong where I saw it so I thought I'd talk about it here.

On the top of the engine, in what would usually be a "valley" they installed a metal plate. This plate has sealer around the edges and bolts to the engine block but in it is mounted the oil cooler. Below the plate is coolant flowing through the engine to remove heat from the engine oil. Why they mounted this thing under the intake I'll never know, but needless to say if you have a pretty good coolant leak from this area it's likely this plate leaking.

You have to remove the upper and lower intakes and move some pipes, remove some banjo bolts and take off the coolant crossover in the back.
I have only done it a couple times so I'll post the images I think might help but this job is not for the timid. It could take you an entire day and if you mess up, you'll have to do it all over again, I'd advise finding someone who can work on this with some degree of skill.

Here are some images.

**Vesicant** · #2 (**permalink**) 01-02-06, 12:45 AM

Sticky'd

Good to know info - and thankyou for the tips.

By the way, looks like ours will be going in Wednesday

ewill3rd · #3 (**permalink**) 01-02-06, 07:46 AM

Glad to be able to help.
They use an RTV type sealer around the base of the plate, it has a tendency to leak after temperature cycling with that pressure on it from the cooling system. I am not sure what the total charge is but I know it's a bit pricey.

huck102800 · #4 (**permalink**) 01-02-06, 05:51 PM

Could it be the coolant cross flow valve for the heater core thats on the back of the engine also because mine waqs cracked and leaking also and i first thought it was that oil cooler to

ewill3rd · #5 (**permalink**) 01-02-06, 07:15 PM

The water valve is a definite player in that area.
The person that I was talking to said that they had already replaced the water valve but still had a leak from the same area.
Sorry I didn't clarify that in my original post.

Make sure to check the water valve back there before tearing into this one.
Thanks for reminding me.

tlarwa · #6 (**permalink**) 01-02-06, 08:17 PM

I just replaced the HCV in my '01 yesterday .... and I'm happy to say that took care of the leak. Surprisingly, I went to the dealer today and had them run my VIN to get a record of all the warranty work that's been done to date (I'm not the original owner), and foound that this valve was replaced once before at ~20K miles. Apparently, this is almost a maintenance item! Good thing it's only $50 and can be changed in your garage!

CtA318 · #7 (**permalink**) 01-10-06, 03:35 PM

Are there any step by step instructions on how to get to the oil cooler? Removing the upper and lower intakes, ect.?

I beleive mine needs to be replaced. I removed the two intake tubes from the front of the engine today and saw what looked like burnt crusted coolant all down below the intakes. I've had a sercious coolant leak from the back of my engine so it's a pretty safe bet that this is the problem. So anyway are there any step by step instructions on replacing this shitty cooler?

CtA318 · #8 (**permalink**) 01-10-06, 03:46 PM

Nevermind I found the document that JefferyG posted.

http://autos.groups.yahoo.com/group/...0Oil%20Cooler/ Heres the link. Easier access because this thread is always at the top.

Tronicv6 · #9 (**permalink**) 01-21-06, 04:42 PM

Quote:

Originally Posted by CtA318

Nevermind I found the document that JefferyG posted.

http://autos.groups.yahoo.com/group/...0Oil%20Cooler/ Heres the link. Easier access because this thread is always at the top.

Now thats instructions on how to fit an "Oil Cooler" what you have in fact on the Catera/Opel/Vauxhall and why its located in the V of the Cylinder Block is in fact NOT an Oil Cooler but to give its correct tital a HEAT EXCHANGER.

Every dam forum calls it an Oil Cooler, which it is and isn't Oil coolers dont have coolant flowing on one side and oil on the other they are also located at the front of a car/motorcycle not in one of the hotest locations outside an engine, hope thast clears this up.

CtA318 · #10 (**permalink**) 01-22-06, 12:30 AM

Why is this unit referred to as an "Oil Cooler" in the official GM service manuals if in fact it is not?

ewill3rd · #11 (**permalink**) 01-22-06, 10:33 AM

Maybe the term is not scientifically correct, but the principal is that heat is taken out of the oil and transferred to the coolant.
Seems to me that it makes the oil cooler than it was when it went in.

Most oil coolers on other cars are located in the radiator side tanks, but it's still the same principal.

As much fun as it is to argue semantics, comments like that can serve to confuse more people than it helps.
Walk into a parts store and ask for a "heat exchanger" and see what you get.
I think they call it that for the sake of convenience.

Mike in Ohio · #12 (**permalink**) 01-22-06, 05:40 PM

I’m about to break into oil cooler next weekend on a ‘98. I have a couple of questions:

Do you recommend draining the oil and coolant before doing the procedure? It’s time for an oil change anyways so I figured I’d do that but didn’t want to drain the coolant unless I needed to. I imagine the best bet is to drain the coolant, do the procedure, flush, then refill if this is necessary to begin with.
The GM shop manual mentions you have to remove one of the catalytic converter in order to remove the feed/return lines by the oil filter – would you recommend that? Also mentions removing part of the exhaust heat shield - same question on that as well.
Any clue what pressure to test the cooler at for leaks? Was going to try and hydro test it myself.
I see several items mentioning washers/gaskets at the banjo bolts at the oil cooler itself - are there similar ones at the connection point by the oil filter that need to be replaced?

Thanks for any advice you have.

ewill3rd · #13 (**permalink**) 01-22-06, 08:52 PM

Draining the oil isn't required, but you have to remove the cooler and the filter so it won't hurt.
Draining the coolant is more important, I'd go ahead or it's going to get everywhere.
You don't have to remove the catalyst, but you do have to reach behind the motor and loosen the bracket for the oil lines in order to reposition them, I think the fittings on the block screw in with flare nut fittings, they could be banjo bolts, I have to confess I have only done this job twice.
I try to stay away from Cateras because I don't know them as well as I do other cars.
Cooling system pressure tests should be about whatever rating is on the cap, if that's what you mean. Most caps are rated for 15 psi or 16 psi.
I don't know of any way to test the cooler itself for holding oil, I have never seen one leak oil though.

Good luck and be patient. Don't rush yourself and don't get frustrated.

CtA318 · #14 (**permalink**) 02-02-06, 03:51 PM

Just finished this job amoung many others on my 97 catera. I started her for the first time in two months today. I need to re-fill the cooling system and then Im going to drive it around for awhile to see whats what. After that I'm plaining on changing the oil.

Good luck to anyone going to do this job. It sure is a lot of work.

german_catera_fan · #15 (**permalink**) 03-30-06, 12:08 PM

hi there,
the purpose of the heat exchanger is to heat up the engine oil faster by supporting the heating process with hot coolant.
that way the oil get hot a lot faster than in a regular engine.
that is a great idea cuz the faster the oil becomes hot the less the engine wears out.
sideeffect is that the oil doesnt become a lot hotter than the desired oiltemp.
cuz the coolant keeps it at a certain level.
hope my english wasnt too bad.