3800 cooling system from HELL

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TollKeeper

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@OR VietVet - Hopefully you can help my memory here...

If memory serves correctly, the water pump bolts to the timing cover, and there 2 water pump gaskets, one on each leg, or a single large one, depending on year.

Then a timing cover, and gasket, that the coolant also passes thru, that mounts to the front of the engine block.

On my last 3800, the timing cover gasket is what had failed. It took me forever to figure out too, as I wasnt there to fix a coolant leak, but a power steering leak, that I had to dismantle all that to get too. Only found the issue after reassembly.

It can fail and leak internally, or externally. So if you are not getting a chocolate milk oil, consider yourself lucky! When it fails externally, it can be hard to trace, as the belts, pulleys, accessories, and harmonic balancer throw the coolant everywhere.

When mine failed, it would not leak when cold, but only when the engine was up to temp. Metals expanding/contracting. I mention this because if you try to find the leak by putting pressure in it, it might not leak.. But it also might.
 
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Matthew Jeschke

Matthew Jeschke

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@OR VietVet - Hopefully you can help my memory here...

If memory serves correctly, the water pump bolts to the timing cover, and there 2 water pump gaskets, one on each leg, or a single large one, depending on year.

Then a timing cover, and gasket, that the coolant also passes thru, that mounts to the front of the engine block.

On my last 3800, the timing cover gasket is what had failed. It took me forever to figure out too, as I wasnt there to fix a coolant leak, but a power steering leak, that I had to dismantle all that to get too. Only found the issue after reassembly.

It can fail and leak internally, or externally. So if you are not getting a chocolate milk oil, consider yourself lucky! When it fails externally, it can be hard to trace, as the belts, pulleys, accessories, and harmonic balancer throw the coolant everywhere.

When mine failed, it would not leak when cold, but only when the engine was up to temp. Metals expanding/contracting. I mention this because if you try to find the leak by putting pressure in it, it might not leak.. But it also might.
Strong possibility this is source of splatter along subframe in that area. I can see a small amount of coolant towards bottom of engine if I look closely in that area. The water pump was easy enough but not like anything I'd seen before. It was dirt cheap as it's not much of anything but a cover and turbine / blades. I keep however, wondering if I did the gasket wrong as there is some coolant in that area but not a drop around pump. Thanks for the tip!

@TollKeeper, sounds like your memory is spot on.

I wonder one thing though. Has the cooling system been pressurized with a coolant pressure tester? If has and was said it has, I missed it.
I hadn't mentioned that. It has, and it holds pressure long enough to lead one to believe there maybe no issue. However, there's always a pool of coolant under the rear driver side corner of the oil pan... Near where it was mentioned there's a coolant seal in the bell housing. I suspect that seal is shot.
 
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Matthew Jeschke

Matthew Jeschke

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Thanks for sharing that... but OMFG. No way can that be done without pulling the engine???

Have to take the balancer off for which I'm not sure if there's enough space in the engine bay to do that?? Maybe I could drop the subframe down a bit to get access?

Long story short, thanks for sharing that 100% on my way to get leak stop now. Probably not even worth fixing / trash the car before I go that far. Sad they made such a leaky motor as is good otherwise.
 

OR VietVet

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If you can get an engine cradle to support the engine from above and then remove the transmission, the access is there. Is a transmission removal doable without removing engine? Check out some videos to see if it is even doable. BUT, it may not be worth it for that car.
 
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Matthew Jeschke

Matthew Jeschke

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I want to report back. I added the Bars cooling system tablets. So far not a DROP of coolant under the vehicle. On another note, they also made my engine run smoother! It doesn't vibrate nearly as much anymore. Oddly I have a newish water pump (installed 10k miles ago?). But I thought there was an issue with the balancing shafts (maybe slightly out of time / phase). However, seems it was the water pump causing engine to vibrate like that! I'd have never thought.

Additionally I took a long hard look at the timing cover. It actually looks doable in the engine bay with the right puller (small enough to fit). There's some space between the upper unit body member and the subframe to possibly pull the harmonic balancer. That be the cause it's just a job of removing all the components in front of it. I'd imagine it'd take me about 8 hours assuming I could fit a tool on to remove the balancer. I'll tell you this engine isn't as well thought out as the small block. It's kind of piecemealed together and difficult to access for larger maintenance projects. Maybe that's just par for the course on front wheel drive vehicles?

Long story short thanks for the help! So far so good!
 

OR VietVet

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I want to report back. I added the Bars cooling system tablets. So far not a DROP of coolant under the vehicle. On another note, they also made my engine run smoother! It doesn't vibrate nearly as much anymore. Oddly I have a newish water pump (installed 10k miles ago?). But I thought there was an issue with the balancing shafts (maybe slightly out of time / phase). However, seems it was the water pump causing engine to vibrate like that! I'd have never thought.

Additionally I took a long hard look at the timing cover. It actually looks doable in the engine bay with the right puller (small enough to fit). There's some space between the upper unit body member and the subframe to possibly pull the harmonic balancer. That be the cause it's just a job of removing all the components in front of it. I'd imagine it'd take me about 8 hours assuming I could fit a tool on to remove the balancer. I'll tell you this engine isn't as well thought out as the small block. It's kind of piecemealed together and difficult to access for larger maintenance projects. Maybe that's just par for the course on front wheel drive vehicles?

Long story short thanks for the help! So far so good!
Welcome to the world of transverse engines.
 

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