^That is too funny that you mention that. I was just driving home from work and pondering. Driving and showering and my two favorite places to think...anyway that same exact thought popped into my head and I was just logging on to pose the question if that would work.

I am going to take a closer look later tonight and see if I can spot any visible leaks around the turbo coolant hoses. If not I think I will wait until the weekend and rest the presure tester and test away. So thank you for that brilliant idea

 

i looked at the pictures again and i see your water temp sensor splashed as well.its coming from that direction for sure.ignore that rag wrapping around thermostat housing shiet.

 

OP it would be a good idea to borrow or somehow obtain a cooling system pressure tester to narrow down the source of the leak. Although, for starters, it looks to me that the upper rad hose may need to be re-fitted to the TStat housing. Make sure the spring clamp is positioned exactly where it was prior to removal according to the indentation it made on the hose. Do the same to the clamp on the coolant feed line to the turbo. Good luck.

 

That splash on the water temp gauge sensor I find to be quite interesting. It looks as though its pooled on there which would entail that there is a drip right above it. I just took a closer peak and tried playing with the coollant feed line to the turbo but no leaks were jumping out at me. I feel like this should be obvious. This has got to be the problem area:


And the coolant must be spraying like so:


Why do I fail at spotting leaks!?

If I dont figure this out before the weekend I plan to borrow one and give it a shot. I will go check all my clamps right now and make sure they are seated perfectly. I used to be OCD about getting them back on in the same exact spot but as time progressed I may have neglected to be that **** about it. If it makes a difference than that would be a really really really simple fix. I will go out now and try to re position them and see if that does the trick. Thanks for your feedback.

 

UPDATE: I spent some time over the weekend trying to rectify the issue. Unfortunately my attempts were unsuccessful. I rented a radiator pressure tester as well and that didnt yield anything. I then just tried idling the car as well as revving it up and was unable to spot the source. It will only spew out coolant after I give the car a good beating. Where ever it's coming from it's still not clear as its not something obvious like a turbo coolant line.

Anyway, I did some more research and I think I may be onto something.

When I was reinstalling my thermostat housing I certainly did not take note of that o-ring, its condition and if it was seating properly. I think that is where its coming from. Has anyone else experienced this? I plan to take it back apart this weekend and hopefully get to the bottom of this.

 

Mine has been doing the same all season. It got bad after the HG swap. Tightening my rad hose seems to have helped. I can BARELY see trace of coolant at the bottom of the radiator hose.

I have no clue what you guys are talking about with the "nipple" and t-stat housing. Ive had mine off twice now. There is a rubber oring on the other side of the water pipe @ the water pump, but I dont recall anything on the t-stat side. One of the rear nipples is for the heater core, right? The front one is for the turbo. The small rear one might be for throttle body (mine is looped). Ive been known to miss and/or forget a detail or 2, am I missing something? T-stat bolts to the head. Water pipe feeds turbo, throttle body, heater core and the lower radiator hose.

 

^ You're right. Idk what that post is saying about an o ring. I deleted my turbo coolant lines and the bottom t stat housing doesn't touch the water pipe at all.

OP. I pretty sure you found the culprit, the rubber hose. But you want to see it. Solution: go pro that area whilst driving lol. I think that normal driving will reveal it because the exhaust system heats up and provides even more softening to rubber hoses.

 

Whatsup Tunnah? You know I never noticed this before so mine may have also been triggered from my hg swap. I only noticed after upgrading my UICP as its clearly spraying everywhere but it may have been doing so beforehand on my old piping.

Given that when the head is pulled that seal is broken for lack of a better term so I can see it not seating properly when being put back together.

It's probably no coincidence that we have a similar leak and both pulled our heads this year.

When I was putting the head back on I had the thermostat housing disconnected from it as I was waiting for a gasket. Once that arrived I bolted up the thermostat housing which was actually kinda tricky to get the 4 bolts aligned properly without the gasket slipping down. But anyway I did not even happen to notice how it sits on the coolant pipe.

I can't confirm nor deny if there is actually an o ring there but given that I didnt even notice it I that makes me feel confident that I neglected to seat it properly.

 

Crap now Im even more confused...I thought the bottom of the t stat housing was just flat but after reading this thread I was thinking otherwise: https://www.evolutionm.net/forums/ev...lant-leak.html

So wtf is this o ring that they are talking about? This is quite annoying. Pulling it apart isnt difficult but its annoying to drain off some coolant to pull it then rebleed etc.

 

It is flat for an evo 8, this i know 100%. What about the tstat itself, that has an oring on it, it gets installed in the water neck when you bolt it down. Maybe the t stat oring is damaged

 

I recall it being flat as well so I have no clue what they were talking about. I bumped that thread as well so hopefully someone will chime in.

I don't think its the actual o ring on the thrermostat. Mine should be in perfect shape as my t stat is relatively new and I don't recall fudging that install.

Plus if that were the issue I would see signs of it leaking around the water neck I'd think.

 

I was checking out the manual for the water pipe diagram and cannot figure out what o-ring they are talking about too....

I scanned in the water pipe exploded view diagram (4 pages including torque specs etc..) hoping someone may point it out for you or at the least completely discredit this idea as a possible culprit.

Look at the picture on page 14-31 at the top left. It shows an o-ring for the water pump or thermostat case (worded exactly as in picture)...this seems to be at the water pump side. Not sure what 'thermostat' case the manual is referring to....

 

Thanks for linking the service manual. Now Im am even more consused

The thermostat case to me sounds like the thermostat housing, correct? But how is that even possible as I dont see any place that mates with the housing other than the 3 nipples, one being for the turbo feed one in the back for the heater and the large which is the radiator feed.

You know what else I found interesting? In the service manual it talks about applying a bead of silicon on the thermostat housing but doesnt mention anything about a gasket there. I replaced the gasket but did not apply a bead of silicon. Now Im leaning back to the fact that the actual housing where it bolts to the head is leaking...ugh for something so simple it is kicking my ***

 

There is an oring on the tstat itself. And a paper gasket in between the tstat housing and head. The only oring on the water pipe is the one at the water pump.

To be clear heel2toe, I had the leak before doing my head gasket. I did however replace the tstat neck with one with a temp bung in it. Leaked from day one this spring onto the uicp. I thought it was the temp sender, tightened it and thought it became slight enough not to worry.

Changed hg and obviously removed lots of stuff in the process. Put a new paper gasket back in with gasket sealer (love the stuff) and replaced coolant lines with samcos. Leak got worse afterwards. Just recently found residue under the rad hose and tightened it up more. Now its minimal. But still seeing some sign of coolant.

You should have seen the uicp on the other Evo at starting line. Lol

 

Come to think of it, I did not put a bead of silicone either when I did my thermostat housing gasket too...so far no leak there. I may have dodged a bullet.

SORRY! Didn't mean to add to your confusion!! LOL