I have a s4 T!! and the add coolant light and buzzer came on so i started to search for a leak because it was not dripping after taking the UIM off i found a puddle under the primary fuel so I checked all the hoses and they were fine. Pulled out the pressure tester and found the leak it is coming out right under the primary fuel rail.

doe this mean the coolant seals are bad ??

OR

i read and quote from hailers2
"If water is leaking bt the intake manifold and the engine ( turbo cars only, Intake o'ring failure), then it can puddle under there and you won't see the leak for quite a while,"

any suggestions and what is that oring failure and does it require a rebuild?

 

there are two coolant o-rings on the lower intake manifold. If they are in fact leaking, you will need to remove the manifold (a pretty involved job), clean the o-ring grooves thoroughly, and replace the o-rings with new ones from Mazda.

 

I've been putting this particular job off for a few months now...doesn't sound like fun.

Interestingly, at one point it was actually so bad that coolant would drain from the pool, run down the block and drip right below the turbo. After monitoring it for a while it just ....stopped.

Seems (at least for now) the leak has fixed itself? Cars don't typically fix themselves, so I guess I should prolly get around to that, lol

 

That's always a tough leak to figure out. You WANT to think it's the coolant hose b/t the rear side housing and the throttle body.....'cause that's the easier one to fix.

Or it could be the "seam" b/t the intake manifold and the rotor housings. And if that's the case, it would be one of two large 0'RINGS that mate b/t the intake and the rotor housings. Lots of work involved to fix that one. Turbo has to be taken off to access the nuts that hold the intake manifold on etc.

The two 0'rings are shown in the jpg attached and I point to where they go.

When I say SEAM, I mean the mating line b/t the intake manifold and the rotor housings. Like where the intake manifold gasket mates with the *block*.

Can't leak anywhere else in that area other than the hose mentioned or the 0rings leaking and letting water past the gasket and puddling in the depressions above. Then drips down the back side and makes you afraid that the o'rings on the tension bolts are leaking (scary scenario imho). But then you realize its coming from above and things are fixable if the leak is up there (without pulling the engine in other words).

Download the ENGINE section of the FSM from this site and look at it. There are TWO of these. ORDER four .....just in case.

 

The main hassle will be taking the turbo off, so the LIM will have clearance. Especially if your turbo has been on there since 1987-1991. Penetrant is your friend. And buy new intake manifold gaskets before starting. The old ones are usually hard as a rock and will not seal if reused.

 

any theories on why that particular leak would stop on its own?

 

Get the engine HOT. Then sit there and rev the engine for a minute and see if the leak returns.

If it quit......then monitor the radiator fluid for a couple of weeks. Make sure the overfill tank has water up to the FILL line on it's side. I've no idea why it would quit. Sure the hose b/t the throttle body and rear side housing isn't leaking/was leaking? Got me. Be happy it's gone done fixed id'self.

 

Unless the reason it stopped leaking is because the coolant port is now clogged with mineral deposits. If it's the front port, there's no reason to care, but the rear feeds the turbo. Though the pressures the coolant system is under would make a blockage in the rear port pretty unlikely.

 

you guys saved me a lot of work i was thinking it was the coolant seal between the rotor housing and iron where can i order all the gaskets i will need for this project??

 

I ordered mine from mazdatrix.com (and a new LIM gasket while you're at it) they've been sitting in a box for 3 months or so , ever since the leak "fixed itself" perhaps when I replace my downpipe, I'll remove the turbo and tackle this....

 

you don't have the subzero start assist on the LIM do you?

 

yes i do

Also what gaskets do i need?

 

will a complete gasket set from mazdatrix cover me??

 

what gaskets will i need for this project??

 

A complete gasket set is going to be excessive. You just need 2 gaskets: LIM to engine and LIM to UIM. And then a pair of o-rings for the coolant passageways.

 

I ran across this issue few weeks ago.. Just wanted to throw this out there Incase you might have the same issue.. There is a water Hose that runs off the back of the UIM down the back Strait to the block... Now This hose would only leak Under throttle or when it was really hot...
It will develop pin hole leaks that squirt water when driving... Then when you pull over to check it out you only smell coolent and most of it drys up before you can get it spotted...
Just my two cents..

 

what about the gasket for the turbo since i have to remove it??

 

You can just re-use the metal exhaust gaskets, but replacing the coolant and oil gaskets would be a good idea. The old ones will probably be baked on.

You'd need:

2x oil return: http://www.mazdatrix.com/getprice.as...m=14-2930-N385
3x coolant feed & return: http://www.mazdatrix.com/getprice.as...m=13-5350-N386

 

I thought the leak went away???????

I'd check out that water hose b/t the rear side housing that connects to the bottom of the throttle body before ripping the engine apart. Maybe replace it and put good clamps on it and see how it goes??????

Two jpgs attached that came off this forum. NOT my engine. I outlined the intake gasket where it mates with the engine *block* and pointed to the two o'rings.

Second jpg I got off this forum shows in general where the leak would happen. It would be along the intake gasket line.

EDIT: I forgot, you said you saw it leaking there when the coolant was pressurized.

 

I have this exact problem. Let us know how it goes.

 

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Replace the hose b/t the rear housing and the bottom of the throttle body FIRST and see if the puddle goes away.

http://www.aps.org/units/fps/newslet...7/monckton.cfm

http://wattsupwiththat.com/

 

i know where the leak is coming from its not a hose i did a pressure test