Coolant Pressure test?

[boat]

I have a mysterious antifreeze leak or disappearance. Twice in the 6 months I have owned my 94 MTX, I have had the low coolant light on the dash come on. I look in the recovery tank and the sensor is not imersed in coolant. I have never seen puddles of antifreeze under my car, there is no antifreeze in the oil, I know this b/c I changed the oil a week ago and there was no antifreeze in it, and pulling out the dipstick, there was no milkyness of the 2 mixing (oil/antifreeze).

The PO told me there was a previous 60k (minus cam seals, mine are leaking) done to the engine before it was put in 13k miles ago, I have the reciepts to show this to be true, for everything but cam seals. What would be the chances that the new water pump is leaking already IF it is?

How the heck do you do a coolant pressure test? He (PO) told me he had an antifreeze leak in the cross over tube that goes under the heads, and said he fixed it. Another SHO owner told it could be dripping on the cats, but I never smell the sweet smell of antifreeze burning on the cats, I would think I would be able to smell it if it was.

Have a little free time on my hands and wanted to get a few things fixed on this SHO before going back to school or getting a job. I have cam seals to replace too, it might be nice to know if I have a bad water pump before getting in there and taking everything apart and then finding that out the H2o pump is bad. I know I need to do a pressure test on the cooling system, just not sure how to do it.

Thoughts?

 

[hawkeye18]

A lot of times, a mysterious slow coolant leak is caused by the radiator end tanks. The tanks are metal; the end tanks are plastic and are simply crimped on. Due to years of heat cycling (metal expanding/contracting, etc), these crimps get weak and don't make a perfect seal any more.

My wife's car loses coolant on a slow and regular basis... during the winter. It does fine in the summer.

If you can't find the leak anywhere else, you'll have to pretty much assume it's at the radiator. Either take it out and recrimp it (cheap), or buy a new one (make sure you recrimp it before installing... they have leaked new!) so you'll have a new radiator, which is nice (less cheap).

 

[rubydist]

On my red 94, I had a similar mysterious disappearance of coolant, but never any puddle. One day I happened to have the hood up when the engine was hot, and I discovered a little leak at the engine end of the upper radiator hose. It would leak there, drip on the top of the engine where it would evaporate while the engine was still hot, so no drips or puddles every appeared. Tightening the clamp on the radiator hose took care of the problem!

 

[itwonder]

You go to AZ or AA and rent a pressure tester. Follow the directions for connecting it and using it; it will tell you to pump up the system to ~15 PSI, don't go too high. Engine off. See if the gauge indicates the system is holding pressure for at least 3 minutes. Use spray bottle with bubble soap. Squirt around connections and look for bubbles showing leaks. Look for coolant drips. Use a flashlight and dental mirror to look through the gaps in the intake tubes for leaks on WP crossover tube.

If yours still has the original radiator, it would be a good idea to go ahead and replace it, along with a new cap. They are cheap enough, and the originals are about to the end of their reasonable lifetime.

 

[boat]

The radiator has 13k miles on it, it was put in new with the 3.2 swap, but I will check that too. Thanks for the help guys, I will be diagnosing this more in the next few days.

 

[Devin]

I have a leak that I haven't pinpointed and I found a trail of dried coolant running down the side of the tranny towards the rear of the car.

 

[boat]

I have found the same thing. Just got to figure out where that is coming from exactly on that side. Rented a coolant pressure tester today. I will post up results when I finish. Hope I can find it.

I have a leak that I haven't pinpointed and I found a trail of dried coolant running down the side of the tranny towards the rear of the car.

 

[hawkeye18]

Probably a heater hose. They tend to leak after time. I would replace every hose back there; once one hose goes, the rest are not far behind!

 

[SHOZ123]

A pressure tester may not find the radiator end tank leaks. These leaks happen when the radiator is cool and not under pressure. pressure will cause the tanks to seal in the gasket usually.

Look for wet areas on the bottom of the radiator when the engine has sat overnight.

 

[boat]

The Pressure Tester, had a hairline crack in it, so it would hold 0 pressure, took it back and got a refund. I did change the hose for the throttle body coolant bypass, hose clamps too. Thought I had it fixed, but it is leaking again, grrrrr.... better go try to trace it down again.

 

[boat]

I believe the original leak to begin with, to have been the throttle body coolant bypass hose. Replaced the hose and used hose clamps. This is what happens when you over tighten the hose clamps...on an old hose...on both ends.

I replaced the hose this time, with a new hose, and different hose clamps, NOT over tightened, equals no leaks. As of now, I believe this fixed my problem, and maybe cured my mysterious coolant leaking problem. The next couple of days of driving around will prove this.

 

[SHOmethewayhome]

wonder if mine is caused by bypassing my TB heater...

*curses the AZ daytime heat*

so much for going outside

 

[boat]

Well, hose number 2

I found another leak, guys. The thermostat housing with the 4 hoses coming out of it, it is the 3-4" long fat hose (has the funny crimp on it) that meets up with the metal hose that attaches to the intake, then turns into another rubber hose to the heater core. This time it wasn't a hose clamp...

What I am in question of, is how the heck did I get a pin hole in that hose on the back side of it? Can they just form with a weak hose like that?

It was facing towards the rear head, towards the passenger side. Just by visual from the driver side, I would have never seen that. After having replaced the TB coolant bypass hose (twice), I decided to take a look yesterday to see if there was anymore leaks from that area. Popped the hood and saw immediately coolant dripping from that hose. Went next door to Advance AP where they know me by name (b/c I spend so much money there) and they gave me the piece of hose I needed and only charged me for the new hose clamps. So far so, good, been checking while I have been running errands today. In 3-4 days of chasing this thing down, 3 of those consisted of draining about 2/3 of a gallon of coolant each time. It sucked but at least I was able to reuse it, it was pretty clean already, but filtered it through a rag twice before it went back into my radiator. Hopefully this is the end of my coolant leaks for a while or I might have to :cry:.

 

[bubba]

I told you should have replaced all of them! Maybe you will get luck and it doesn't happen again!

 

[boat]

I would rather pin-point the problem and figure out what it is before I go buy a bunch stuff I don't have money for right now. When a hose leaks I will replace it. It is frustrating to think that you fixed a problem, then to find another leak to fix.

If it ain't broke, don't fix it!

I told you should have replaced all of them! Maybe you will get luck and it doesn't happen again!

 

[bubba]

True.... Hopefully you got it.... and it doesn't run you around, is all I'm saying!