dhays

iTrader: (1)

<sigh> I just noticed a coolant leak. The car doesn't overheat, and I dont' look much coolant. I noticed a drop in the coolant level in the fill pipe the other day and it took maybe a 1/2 pint to top off. Never saw any coolant on the ground, car never over heated, never got a low coolant light.

I picked up a pressure tester at Autozone today to do a pressure test of the system, but the adapter doesn't fit. While I was messing with that, I noticed a pooling of coolant on the back side of the undertray. That was why I never saw any coolant on the ground, it was being caught by the undertray.

My plan at this point is the take the undertray off, jack the car up, start it and let it get hot and look for leaks. I'm guessing that it either has to be coming from the rad or the ast-radiator line. I've got newer Samco radiator hoses but it looks like the AST line is older.

Any other suggestions? Is the AST-radiator hose a formed hose or can I use any coolant line hose for it if that is what needs to be replaced?

dhays

iTrader: (1)

OK, I jacked the car up, took the undertray off, topped off the fluid (took maybe a cup) and allowed the car to get to operating temps (fans kicked on). No leaks from the radiator, or the radiator hoses. I did spot just a tiny bit of coolant underneath the AST (Kinetik aluminum). It looked like it might have come from the hose connection at the bottom of the AST. However, it was no more than a few drops.

Now I'm just letting the car cool down and see if I get any more leaks.

In the mean time, when I took the undertray off, I noticed that the rubber seal that goes between the bottom of the radiator and the undertray is mostly gone. What is left is brittle and falling apart. Can that piece of rubber be replaced or does it come with that part of the undertray? Has anyone found anything else to use for it? As it is now, I'm losing a lot of air out underneath the rad because that rubber seal is toasted.

Mahjik

iTrader: (1)

You can use something like what's used to seal the bottom of garage doors. Just get creative. While it's important to seal the bottom of the radiator so air doesn't go underneath it, what you use to it doesn't really matter.

dhays

iTrader: (1)

Thanks as always. I really have two concerns, the first is figuring out how to apply it and make it stick, the second is finding something that can take the heat of being pressed up against the radiator.

Upgrayedd

iTrader: (1)

David have you checked the front of the motor to see if there may be a small leak from the water pump?

Mahjik

iTrader: (1)

I wouldn't worry too much about the heat. Rubber can take quite a bit of heat and in that area, it shouldn't be a problem. You could attach some using rivets or something similar. I would avoid adhesives as that would probably melt unless you used some sort of permanent adhesive (which probably isn't ideal).

dhays

iTrader: (1)

Yeah, I have. It didn't leak last night when I filled it, ran it to OT, and then shut it off. I got a few drops of coolant from the underside of the AST where the hose connects. I tightened up that clamp.

This morning, after the engine was cool, there was still no coolant leaked anywhere and the level in the fill pipe was still up to the top. So I have no idea. I do know that I'm going to take a gallon of distilled water with me to Packwood on Sunday for the Autocross.

I just checked with Ray Crowe (I needed a couple things anyway) and he said the rubber strip comes with the undertray so I'm going to go to Home Depot and look for some rubber. Might have some luck in the HVAC sections. The rubber is about 1/2" square in cross section. Your idea of pop rivets is a good one.

gracer7-rx7

iTrader: (16)

The Autozone pressure tester requires the "import" adapter. Ask for it specifically next time as most locations carry it. I used it twice to check my car.

For non stock hoses use good hose clamps. I suggest Breeze constant torque clamps. They were the only ones that I found that stood up to the 20 PSI coolant system pressure test. Google for them as I don't have a link handy.

When replacing with stock hoses (which I prefer b/c the fit better), go ahead a get a new set of OEM hose clamps. They have the correct torque for the hoses and won't leak.

My experience has been that when one hose goes bad, there are others on the way. Might want to schedule some time to take a look at the others and replace when time and budget allow. I think the full set is $160 from Ray.

I should have taken my own advice as I didn't replace one hose (throttle body coolant) b/c it was a pita to get to, then forgot about it, a year later it burst. Thankfully I was near my friend's house and we got it patched well enough to get home but what a pita...

dhays

iTrader: (1)

I thought my coolant problems were solved, but they weren't. I drove the car 2 hours to an all day autocross event, and then drove 2 hours back home. The car never got overly hot, the max water temps that I saw were around 220 on the way home when I was fine tuning my boost controller and making a series of WOT pulls.

I noticed this morning that I once again had a small amount of coolant puddled on the undertray. Maybe at most 1/4 cup. The coolant overflow tank was still at the same level. The level in the filler neck was down by that 1/4 cup.

I can't tell where it is coming from.
It appears to only happen after the car gets to "fully warmed" temperatures.
Why isn't any lost coolant being drawn from the coolant overflow tank?
I would think if it is a typical leaking hose, I would see the coolant leak after the system has reached its pressure and is running. As it is now, I only see it after the engine has cooled down and then only after the car has been driven hard/long.

Gracer, I'll try again with Autozone and ask about the import adapter. I did go back to them and they gave me another adapter, but it only looked like an adapter to test a pressure cap, not what I would need to attach the pressure tester to the car.

gracer7-rx7

iTrader: (16)

The last time I had a symptom that sounded like that was when a worm gear type hose clamp had lost its tension and started leaking coolant when the car was hot and the coolant system pressurized. I think it was one of the AST hoses at the time - it actually happened more than once until I learned my lesson and replaced with OEM clamps. Never happened again after that iirc. My memory is slipping though... getting old and cranky...

dhays

iTrader: (1)

Yeah, may be time to replace the clamps. The PO replaced the radiator hoses, but used standard worm clamps. It could be coming from where the lower rad hose connects to the WP housing.

Gadd

It's most likely the line from the AST to the overflow tank that's leaking.


Paul

dhays

iTrader: (1)

I'll check it again, but it doesn't look like the coolant is spilling below it.

DaveW

I had a leak that looked exactly like that, and it turned out to be that the water pump seal was leaking. New WP, no more leak.

I also had the coolant level sensor break in its threaded area, causing a slow leak there.

Dave

dhays

iTrader: (1)

I've looked around the WP and it doesn't seem to be leaking from there, but with a small leak that refused to leak while I'm watching, it could be anywhere I suppose.

SLOASFK

iTrader: (5)

When my friend had his FD, he had an aluminum AST on it. Aside from the hose that went to the Thermostat and the hose that went to the rad, there was a third nipple that was capped off using a worm clamp and a rubber cap. After about 8 months of ownership, this rubber cap had become brittle and cracked. It started out as a slow leak that got progressively worse.

Dave, did you check for anything like this on or around the AST?

dhays

iTrader: (1)

My AST has three ports. One to the radiator, one to the filler neck, and then one to the coolant overflow bottle. The pressure cap releases fluid into that line. They are tight but I may get better clamps as right now I just have small worm clamps on them. I did order a new pressure cap from Ray Crowe. At least I'll know the cap is functioning properly.

dhays

iTrader: (1)

Following Gracer's advice, I went back to autozone and this time picked up the import adaptor for the pressure tester. It worked.

I first did a pressure test on the system. Being the idiot that I am, I attached the pressure tester to the fill neck and just pumped the pressure up to ~20 psi and let it sit.

When I came back there was a very small puddle of coolant on the floor. I got to thinking that 20 psi might be a little high and I wasn't able to find where it came from anyway.

Then I got to thinking that I have a 13psi pressure cap on the AST so why was I able to pump up the coolant pressure to ~20psi?

I took the cap off the AST and hooked it up to the pressure tester. It didn't vent pressure until I was over 17-18 psi on the tester.

I then took a close look at my AST cap. I knew I should have a 13psi pressure cap since I have a '94 and it should have had the coolant recall done. Besides, my cap had a 13 on it. It wasn't until then that my pea sized brain noticed the "." between the 1 and 3. Yup. I still had the original 1.3 bar pressure cap, or 19psi. I've ordered a new cap from Ray but now I need to check to see if the coolant recall was ever done on my car back in 94. Any ideas on how to check that?

Another question. It doesn't look like the AST is drawing coolant back in after the engine cools down. I installed Kinetik's aluminum AST. I can see how the cap should vent coolant into the overflow tank, but I don't see how it would draw it back in under vacuum. Maybe it is the old cap, but I just don't see how it would work.