coolant leak

[boomer3]

Hey guys. I'm having a bit of trouble diagnosing source of a coolant leak. Basically, I've had to take off my intake plenum several times now to fix coolant leak issues, it's a real headache. I guess the hoses are so old that they are now deciding to all blow out at the same time! Not to mention the cold weather may have an effect on them.

I've replaced all possible culprit hoses: the 2 small hoses that connect to the metal lines at the back of the block (turbo cooling i suppose), the 2 medium sized hoses for the oil cooler. I havent changed the 2 heater core hoses since i don't have the kit yet, but i dont believe they're leaking. I put everything back together, and some coolant is still dripping from the bellhousing below, and a little steam rising up near the firewall by the clutch cylinder etc... At this point i'm a little confused. Assuming the hoses I changed arent connected badly, what else could be leaking?? Is there a line or 2 i'm not seeing, maybe something running to the tranny? or from the firewall and backward? It's pretty hard to diagnose with that plenum in the way! Maybe i'll grab a mirror.. Any suggestions are appreciated!

[bobbo]

Put it up on a hoist and run it.

[bellis_GTR]

Hey man, Iv had ever lasting coolant leaks since Iv had this car, i know how shitty it can feel. Especially after all the work you did to fix it. I have actually had the same problem with coolant leaking from the bell housing. This leak is actually coming from one of the pipes underneath the plenum, and rolling down hoses then on to the bell housing. I have changed 2 heater hoses, one hose that branches of the main heater hose and a turbo cooling line (I think). I checked thermostat and it opens. The water pump was changed in June. Iv gotten a new rad and did a proper flush and still have over heating problems with no leaks until the car gets to operating temp. Then leak drips more and more. I have also had coolant running down my Down pipes and making a lot of smoke from it burning. I made sure the heater hoses on that side were on and secure.

Turbo line




This is where the leak was coming from and dripping down to the bell housing. You cant really see but its to the left a bit from center.



I replaced these hoses with the plenum still on. So Im thinking I might have left one not tightened fully. Iv been told my valve cover gaskets are gone and are leaking on to the hoses, but I dont think thats it. I have searched and search what the problem could be and found that it could be the oil cooler has split internally mixing oil with coolant or my HG is gone completely.


Here is where I was told it could be the oil cooler.

http://www.gtr.co.uk/forum/144671-cracked-head.html

Let me know what you find out and if you get any progress on this as Im in the same boat. Hope this helped a bit

[boomer3]

I have replaced all of the coolant hoses that you have shown in your pics. I agree, this unending coolant leak is terribly frustrating. I would expect that once a hose that is obviously leaking has been replaced, the issue will be solved. But apparently not in our case!

I'm going to put the car up on a hoist with it running and see if I can figure it out. This is such a headache, with not being able to troubleshoot it correctly.

[Marke]

Your block may have become porous. I have seen it before in RB26 just under the plenum. You can get a stitch in the block to stop it.

[bellis_GTR]

Can you explain further?

[boomer3]

Can you explain further?

I can't get the car to a hoist until sunday most likely. I'll post my findings right after. At this point, i'm banking on the metal coolant lines being good still. It is possible that I over tightened one of the hose clamps and split a line slightly. Otherwise I'm wondering if there is a coolant line that I haven't found yet. Possibly going to the tranny? The service manual doesn't have any extensive diagram of the coolant system..

[Marke]

When electrolysis occurs in the cooling channels of the block it can become porous. Electrolysis usually occurs when coolant is not changed for extensive periods, which I have noticed is pretty common for lots of cars coming over from Japan.

[archaeic_bloke]

hey, this photo might help u out, each blue hose is for coolant... the black ones are for air.... best bet is to replace all of them...

other possibilities... if not a hose, then perhaps a gasket, OR a crush washer, theres like 40 different seals that use copper crush washers, half of them are coolant the other half are oil, I doubt its this, because a crush washer leak would be on the exhaust side.

theres also the headgasket, which im surprised nobody else has mentioned... it IS possible that a headgasket might leak on the exterior, meaning between water channel and the outside of the block, you wouldnt notice anything except the leak...

lastly, it could be any of the permatex gaskets, the red dry silicone that seals things like the rad hose neck on to the thermostat.

anyways look at this picture, it should help clarify for you what hoses are what... keep us updated bud,

[boomer3]

Thanks Archaeic bloke, that is a helpful picture. Those are certainly the hoses i've been dealing with. To make a slight correction, 2 of the blue hoses in that picture attached to the plenum are vacuum. And 2 of the four small black hoses at the back of the block, next to the heater core lines, are coolant for the turbos.
I had the car up on a hoist last night, but unfortunately she didnt feel like leaking, and I couldn't see the problem spot. I will have to hoist it up again, and figure it out using a super bright light, and possibly a mirror.
Today on my morning commute it was about -24. The engine got up to operating temp, but I didnt get any cabin heat (what I thought to be a servo problem). Then all of a sudden the temp starts climbing beyond the thermostat setting, I pulled off, and it was leaking a fair amount of coolant (maybe 1/2 Liter). I let it cool down a bit, turned the car back on, it held operating temp, and all of a sudden i started to get cabin heat. I'm 100% confused. I dont know whether this cabin heat problem is related to the general leak problem i'm having, or if i can still rule that out as servo malfunction at low temp (as is common). How the hell could it start overheating and then hold the correct operating temp again. Could it be that enough air got in during that "leak session" to cause water pump cavitation and no water flow? Or would that have been the thermostat malfunctioning. Freak, i'm pulling my hair out with a problem that should fit like a puzzle.

[bellis_GTR]

When electrolysis occurs in the cooling channels of the block it can become porous. Electrolysis usually occurs when coolant is not changed for extensive periods, which I have noticed is pretty common for lots of cars coming over from Japan.

Thanks for explaining. I think that could be one of the reasons why mine are bursting.

arechaeic bloke I said head gasket

" have searched and search what the problem could be and found that it could be the oil cooler has split internally mixing oil with coolant or my HG is gone completely. "

And the copper crush washers your talking about. How do they fail? At one point I had coolant rolling off the down pipes.

[evilgtr]

Sorry to thread jack your thread but Iv had a coolant leak since summer time when I got my car back from Lightspeed, I havnt been able to find it for almost 7 monthes.... But today the stars aligned and I FOUND THE MOTHERF@*KIN LEAK !!! Now I'm going through my Facebook friends to see if I have any Asian friends with small hands that can fix it. It was on of the small hoses at the rear of the engine behind/under the fuel rail. I bought a rad pressure tester with a adaptor for my Blitz rad and bought a Bore camera. Pressured the p.o.s up to 120kpa , turned the garage lights off and molested the back of the engine with the camera until I found a tiny bit of glistening water on the back side of the hose - never would have found it with out the camera. A hoseclamlp was over tightened and split the hose.

[boomer3]

Are you referring to the spot where there are 4 small hoses at the back of the block, that run around the back side of the block? 2 of these are vacuum, and 2 are coolant... Bellis_gtr managed to change these without taking the plenum off, but i think it would be too tight for me.

[evilgtr]

Yes boomer that's exactly what I'm talking about, how the f did he manage that ? I talked to Andrew and he said theres only 3 ways 1. Remove plenum 2. Hoist the car up and pull starter off 3. Pull engine.

I chose to remove the plenum, never done it before but took me about 1 hour 45 mins. It was quiet simple actually. That's with no directions or instruction so I imaging someone who has done it a few times could do it in about 1 hour or less.

[Marke]

And the copper crush washers your talking about. How do they fail? At one point I had coolant rolling off the down pipes.

They usually don't fail. If you try to reuse them they won't seal properly and you will get leaks. I recommend replacing them any time you undo a banjo bolt. I found this out the hard way when I was in a rush to get my car back together for a race the next day. Oil and coolant leaks galore.