Mongo

As you all know, you have seen my previous cooling issue thread. What you don't know is that my garage floor now has a huge puddle of coolant with my car sitting right above it!

Here's what happened.

1) Came back home from school and a spirited drive.

2) Parked car in garage, temperature was at 1/2. Idle was low like it usually was.

3) I leave engine on with hood open and come back with idle screw tool.

4) Fans turn on immediately and coolant is rushing out of the little overflow hose on my reservoir and onto my garage floor!!!

5) I immediately shut the car off! Leave the fans on full blast with key still in ignition.

6) Car cools after 10 minutes and all the coolant that was still in the reservoir emptied itself well below the minimum line and back into the radiator


Ok what just happened to my car? I have no external leakage from the head gasket. Could my thermostat have just failed??? How about my head gasket just went for sure????

Any help would be much appreciated and a recommendation on what to do now.

The DareDevil

Maybe it just had a stomache flu... Probably feels a lot better now!

michaelathome

Look at draining and replacing the coolant, try to look at the T-stat while it is all empty. It almost sounds like you have a clogged or bad radiator. It could be the hoses T-stat though too. Empty it out and look stuff over.

Good luck Stig you sure you wanna be the Nov car?

Michael

Mongo

ok guys, I checked the car. The reservoir is dry as a bone. Upper radiator hose is still carrying heat. Lower one going into water pump is cool. The car is off BTW. I have an idea tomorrow of pulling out the thermostat to test it and try running the car without the thermostat to see what happens.

Mongo

Update.

michaelanthome has been helping me diagnose this for about an hour and a half plus. Here are my latest findings.

1. Oil dipstick is normal with no traces of coolant.

2. Coolant reservoir empty.

3. When I squeeze both upper and lower radiator hoses separately *not at same time* I can hear gurgling coming from the coolant reservoir only.

4. There is no trace of oil in the coolant reservoir.


The diagnosis so far is a possible clogged or failing radiator. Any other suggestions are welcome in my dark time at this moment

Serge944

Why are you checking for a faulty headgasket? How would that cause the the system to overpressurize?

Are you sure your radiator cap is good/sealing properly? You'd be surprised - but people have actually not closed it all the way/lopsided in the past leading to coolant overflow.

If your radiator was failing, then why would your coolant temperature be normal? A bad thermostat makes no sense either - if there is no water coming into the block, how is it supposed to overpressurize? You would also not be running at normal temps if this was the case.

Finally, make sure the coolant is actually coming from the expansion tank overflow tube.

sharky47

I had the same sort of thing happen about a month ago. I had all kinds of strange coolant problems and evetually a near-overheat. It turned out to be so incredibly simple, yet so confusing....

Check every single hose clamp! Really! About half of mine were loose, and some were so loose that you could grab the clamp and just move it all around. I have no idea how none of the hoses ever blew off, but we tightened them all up, rebled the system, and everything's been fine so far.

Z-man

Well, you overheated. The coolant overflow/reservior tank is empty because your car burped up all the coolant! Note: when you pulled into the garage, all that hot air around the engine didn't have anywhere to go why did you leave it running? Next time, leave the car outside. Don't leave it running - just turn it off, pop the hood and let it cool off like that. Folks who track their 944's don't even leave the motor running - it doesn't help cool it down - rather, it keeps it hot.

You hear gurgling because you have introduced air into the coolant system.

Could be one of the following items:

1. As stated, it could be a clogged/blocked radiator

2. Could be a leak somewhere.

3. Probably not a failed thermostat - when our thermostat fails, it is designed to fail in the 'open' position.

4. I suspect it's a bad H2O pump.

5. Or, it could be nothing. Like I said - leaving the motor on after a spirited drive in an area where the hot air cannot evacuate is a bad idea.

Good luck,
-Z-man.

aribop

On Ashton's red car, the headgasket was compromised between the cyclinder bore and one of the water passeges on the head near the intake manifold side. This caused the system to overpressurize. No antifreeze was being burned since it was on the high side of the engine and no antifreeze was leaking accept where it was being pushed out of hose connections when it got so much pressure in it.

It could be a number of things, but I would not rule out a faulty head gasket.

Tom R.

I had a similar problem with an RX7 some years ago. Had the problem after I flushed the radiator and used one of those solutions to clean out the system.

turns out while i did all that great work to "preserve" and "maintain" the car I did just the opposite!!!

a small particle came into the check valve for the return and it wasnt closing/building pressure correctly. the car would run at the correct temperature but coolant was overflowing because the check valve wasnt working right.

probably not your problem, but an often overlooked area.

Mongo

Hey Z-Man, the water pump is brand new.

The reason I too believe that the radiator has been clogged is the fact that when I pulled into the garage, the car was at half temperature and functioning normally; hell the car functioned normally all day with no coolant leakage. I opened the hood because I had a slightly rough idle because my idle screw was backed all the way off after we took apart the intake manifold to fix an oil filler tube leak. When I come back with the tool to fix the idle, the fans come on and the coolant is topping in the reservoir. On a side note when I first opened up that hood, the coolant was right at the same height I filled it up to in the morning before the whole thing spilled over.

Now why would I believe radiator? Because underload, revolutions of the motor introduce more pressure to force the coolant through the radiator and the water pump to push it faster into the block. At idle, all of a sudden the car just gets a huge pressure hike causing coolant to stay in the reservoir with no where to go but out the escape hose below the cap. I also just replaced that cap with the right cap finally for the 944 and that didn't change a thing.

My radiator has never been changed on my car, hence my reason to also believe the radiator. Regardless, I'm buying a new thermostat and new radiator today and see if I can get this sucker working by Monday night.

Yabo

Make sure you let me know if it's headgasket...

BTW - Told you the air in the system didn't make sense.

good luck man. hope its something easier than the gasket.. of course the radiator and tstat are going to cost you more than the headgasket job.

M758

STIGGY STIGGY STIGGY...

Before you get you panties in a bunch... Here is a little thing I found out.

The coolant tanks can fail at the cap. What this means is that they go out of round and never seat. You can replace the cap all day long and it will pump water out the overflow.

There is a very easy way to test this. Pull the tank out of the car.
Use you fingers to plug the main hole and add water. Put the cap back on and turn it upside down. If it leaks out the top you have a bad tank. What happens is that tank never seals and as soon as it tries to build pressure it blows out the overflow.

Really if your radiator gets hot it is working fine. If the hose from the water pump gets hot you are just fine. If you have bad headgasket the car will not pump out water, but it will mysteriously disappear. The car will run normal temp and be just fine. Then overheat and not have any water left. That is because it is being burned off. Of course a major headgasket failire reasults in a motor that spits water out the tail pipe and does not run.

Yabo

So, campeck's headgasket failure mustve just been another case of campeck rulez?

michaelathome

The water pump is always going to be pushing fluid. My guess, only a guess, is that he may have a clogged radiator in need of a flush. Stig described areas of dried or crystalized coolant near his heater hoses.

Stig recently changed the WP, introducing more adaquate pressure dislodging some of this ^^ junk. At idle t-stat opens and WP forces fluid out of bottom of the radiator and into the system but can't get through a clog somewhere in the top of the radiator so where else is it supposed to go but to the overflow tank.

It's just a guess but to me it sounds reasonable. Problem is that we don't have the tools at Andy's disposal to do a propper flush to the system.

I also suggested that he open the heater valve to the cabin and bleed the system. Close it and bleed it again. Keep bleading it til there is no, none, nada air in the system and try troubleshooting it again.

Joe P's test sounds like another thing to look at for sure!

aribop's situation makes sense too. We are hoping that this isn't the case though.

A new radiator and hoses is never a bad thing on any 20yo car. To jump out and replace it, well, I would do more troubleshooting. On that point, how many have had success at re-coring them? Is it even possible? Mine is an AL shroud with plastic endcaps. How does that hold up to re-coring?

Michael