Throttle body coolant leak ATX

[SHObogdan1]

Hello everyone, I completed an upper 60K on my 93 ATX a month ago and noticed coolant was leaking out of the throttle body after putting it all back together. I replaced the throttle body gasket (so no more leaks from there right now) but I have noticed quite a bit of steam is coming from under the hood on the driver's side. When I put the intake manifold back on I reused the old intake gaskets (they looked in good shape) and I don't think it's burning coolant. The oil looks good and it's at the full mark. It's not overheating, the temperature gauge is around the "R" when warmed up. My only concern is I may have gotten a bit aggressive on the DPFE/EGR tubes when taking off and putting on the rear valve cover. Could they have cracked? Or maybe the residual coolant from the old leak splashed somewhere on the EGR valve or exhaust manifold? What do you guys think?

 

[rubydist]

This can happen if you have any of those coolant hoses where the clamp has not been put on correctly. It is easy to miss one of the clamps under there when reinstalling the intake, and I have also seen this from the thermostat housing leaking or the radiator hose leaking.

And, you could have split one of those hoses when you removed and reinstalled the intake manifold, in which case it will leak even if the clamp is on right.

You will need to carefully check each of the hoses and their clamps.

 

[SHObogdan1]

All the hoses attached to the throttle body are dry so is the upper radiator hose. The clamps are all secured as well. The t-stat seal is brand new and t-stat housing is on tight. No real apparent leaks, no overheating, just steam along the EGR/DPFE area that appears through the driver's side hood close to the windshield. No black smoke, just white steam.

 

[Slo-Sho]

How about the heater hoses? The metal tube that the CELO (Cold engine lock out) sensor with the crimped on rubber hose is a common failure on these cars. It's a real PITA to see and get to as well, FYI.

 

[rubydist]

I have had several of those hoses leak over the years, both due to poor clamp and due to being split, and in several cases, they would appear dry unless you opened the hood and felt of them when the engine was hot. By the time the engine cooled, all the leakage had evaporated and they appeared dry - it was a pita to find the leak....

 

[SHObogdan1]

Ok that makes sense, so that means when the engine is warm, that heater hose leaks coolant on the EGR or exhaust manifold making it steam, right?

 

[jimtash]

No, the coolant itself is producing the steam because it's running at 190 degrees. And the reason you see the steam is because of the pressure of hot coolant is forcing it out from wherever it's leaking along with the coolant. Hot coolant doesn't need to hit a manifold to produce steam if it's leaking. And if it's coming from the throttle body area, there's nothing super hot there for the coolant to run off on. If you're getting a lot of steam though, more than likely it is running onto an exhaust manifold or pipe.

 

[rubydist]

in one case, my upper radiator hose clamp was leaking at the thermostat end, so the coolant would just land on the top of the transmission - and that was hot enough that it would evaporate the coolant before the engine got cold, so whenever I looked at it with a cold engine (made sense not to burn myself, right?) it was dry. finally one day I opened the hood with the engine running and saw a little coolant on top of the trans. it was not a big leak, but I would need to refill the overflow tank once a month or more.

 

[SHObogdan1]

Ok, then my biggest culprit must be either the heater hose with the 90 degree bend in it or the CELO hose. Will a pressure test actually work in that situation? I know you guys said its pretty hard to spot even with a pressure tester.

 

[rubydist]

it should find it.