proper coolant addition procedure? coolant problems

[silence]

having problems with my car- was running properly- i parked car in garage after a long drive and it promptly dumped approximately half a gallon out of the overflow's "vent" or "release". i attempted to let it cool- refill coolant and move on etc. however, now the coolant is building pressure, overfilling the tank, and generally not working plus the car would overheat if i actually ran it for long. I must have air in the coolant etc., but why can't i figure out how to fix it? what is the process you use?

To remove this ad, register today or login if you already are registered!

[Z06EATER]

i would drain the radiator and coolant reservoir and then add fresh new coolant.as for the air trapped as you say i'd run the car and lleave the cap off put your heater on full blast to the hottest and let the bubbles come up. did it on my E420 and it stayed under normal temperature after that project.

[silence]

it was in normal range prior to dumping of the coolant- in fact, it dumped "cool" coolant (cold to the touch 2 or 3 minutes after the fact)

how would a stuck thermostat result in this problem? (blocks the pump from running the coolant through the radiator, thus forcing the coolant to "back-up" into the reservoir "en masse" and also not getting any cooling?--- how will i tell for sure?

where does the car read the temperature?

how is the system supposed to function when it's pressurized? ie- how full should the reservoir get vs. how empty should it be non-pressurized? Can it "gulp" air down the "return" line if coolant is overfilled?


also, likely of note- at times the temp gauge fluctuates up and down rapidly, to me suggesting air bubbles passing through the area where the temperature is measured?

I def. hope it's not a head gasket-

[ProjectC55]

Originally Posted by silence

I def. hope it's not a head gasket-

I hope not as well but it sure sounds like it!

[SeeKlasse]

knock on wood for sure!

however, it would be a good opportunity to just shoot straight for a 55 motor the cost would be similar wouldnt you think?

[ECTurboGSX]

I can't see how an overflowing coolant overflow tank would indicate anything with the head gasket. If the head gasket were toast, you'd either have oil traces in the coolant, foam in your oil, or you'd be blowing white smoke out the tail pipes. If anything, you'd be losing coolant and it wouldn't be getting purged out of the overflow tank.

I'd start at the thermostat and work your way from there. You can check for a bad thermostat by letting the car warm up and then you can see whether the upper radiator hose is hot. If the car is hot and the hose is cool, then the thermostat isn't opening and letting coolant flow through the radiator. I had a similar situation on the Eclipse and I could hear the coolant boiling in the overflow container when I turned the car off. This is something you want to fix asap since overheating can cause the heads to warp and other neat things. Then suddenly, you will be worrying about head gaskets. Oh yeah, one more thing; when you check the upper hose, check for radiant heat before you grab the hose. If it is working, you'll get a good burn if you just straight grab it. Good luck.

[ProjectC55]

Originally Posted by ECTurboGSX

I can't see how an overflowing coolant overflow tank would indicate anything with the head gasket. If the head gasket were toast, you'd either have oil traces in the coolant, foam in your oil, or you'd be blowing white smoke out the tail pipes. If anything, you'd be losing coolant and it wouldn't be getting purged out of the overflow tank.

.

That's not always tru. I strongly disagree!
When my head gasket blew on my Talon I never had a trace of oil in the anti freeze or antifreeze in the oil. Under boost air was getting past the head gasket and pressurizing the coolant passages and you could see that when you opened the cap on the thermostat housing. My overflow tank kept filling up and the car would overheat. I had the same thing happen to my Toyota FX-16 GTS,not a trace of oil in the antifreeze and vice versa. Thermostat guage would be erratic at idle until I would start driving the car the thing would cool down. I had no external leaks or any internal signs as well. This was the case in my Talon as well.

Alot of times it depends on where the leak is between the head,the head gasket and the block.
Bottom line is the coolant system needs to be pressure tested or a compression test needs to be done if the source of the overheting is not found.


I hope the problem for the poster is that he just has air in the system from installing the pump for the heat exchanger. Easiest way to purge the air out is by filling the motor up first thru the thermostat hsing by pushing the thermostat open with a screw driver and pooring in the anti freeze. Then you can poor the anti freeze in the radiator hose filling up the radiator.

This has always been the method I have used on my MB to keep air from getting in the system when I took my radiator out.

[vinceC]

The system operates with about 15 PSI pressure normally. The pressure raises the boiling point of the coolant mixture. That is why the car can operate safely at coolant temperatures above 100 degrees C.

Have you checked the cap on the coolant reservoir?

You can buy an inexpensive kit at an auto parts store that will check for combustion gas in the cooling system or have the test done at a radiator shop. That will tell if a head gasket is leaking.

I doubt that changing the heating system circ pump will cause this.

[silence]

my understanding is that b oth arguing sides on the head gasket issue are right- it is potential than under high boost a leaking head gasket could cuase these issues etc. (but seems improbable under my 5 psi).

this problem is occuring when the engine is not seeing boost

the upper radiator hose and the entire radiator are cold! and i'm 99% sure the problem is my thermostat. I actually ordered the t stat yesterday prior to even getting a chance to look at the car again (which i did this morning). also used the opportunity to pick up the steering stabilizer.

directions for t stat change somewhere? wish me luck that the t stat fixes the problem- i've got a long trip planned in 10 days.

-drew

[ECTurboGSX]

Compression pressure ratios are going to be much higher than the ~1.33 pressure ratio that you are seeing in the intake due to the supercharger, so that shouldn't be a big factor. However, to argue C55's point, imagine what the possibility is of you having a head gasket failure that only allowed flow in one direction. Your cylinders spend a certain amount of time in compression and in vacuum. If the combustion pressure is forcing air into the coolant, then wouldn't it also be sucking coolant in when the intake charge is being pulled into the combustion chamber? Hence white smoke? You can have a blown head gasket between two cylinders that will only result in low compression numbers and not have the symptoms that I stated earlier. Otherwise, one of those things is going to be true.

[NitrogenBalance]

Originally Posted by silence

my understanding is that b oth arguing sides on the head gasket issue are right- it is potential than under high boost a leaking head gasket could cuase these issues etc. (but seems improbable under my 5 psi).

this problem is occuring when the engine is not seeing boost

the upper radiator hose and the entire radiator are cold! and i'm 99% sure the problem is my thermostat. I actually ordered the t stat yesterday prior to even getting a chance to look at the car again (which i did this morning). also used the opportunity to pick up the steering stabilizer.

directions for t stat change somewhere? wish me luck that the t stat fixes the problem- i've got a long trip planned in 10 days.

-drew

I feel bad for you man. I had anixety attacks when I was first tearing my car apart. Everthing that could have happened did. Well not everything. Lets just hope its the T-stat. Which is why I posted, I would look into getting one from PTE. I was truly amazed at how well it keeps temps down during summer. Coolant temps might I add...IAT's are another story

Is the A to W intercooler setup tapped into the cooling system or do you have it set up on its own?

[silence]

it is seperate system

i ordered stock replacement- if there is a better option i can swap later

[MBHustla858]

good, cuz everytime you do a headgasket, its recommened to swap out the t-stat too......

[vinceC]

A head gasket can leak under firing pressure (in the order of 15+ bar) and not leak under vacuum (negative pressure of 1 bar relative to atmospheric pressure). Combustion gases can leak into the cooling system without oil contamination of the coolant. In cases where oil shows up in the coolant it is usually because a nearby oil passage leaks. Sometimes just the oil passage leaks into the coolant as in the M104 engine.

The best test for a head gasket leaking is the chemical test. Basically it is an aspirator bulb connected to a clear chamber. The chamber is filled with a chemical. The chamber is connected to the reservoir/radiator and the gases in the coolant system are aspirated through the chemical. If the color changes combustion gas is present.

In Silence's case, the fact that the upper hose never gets warms does suggest a t'stat problem.

[AMG140.6]

I'm sending you all my good mojo for the day.....so lets just leave it at a bad t-stat and that all will be well in AMG-land.

[Ausmbtech]

I have honestly never seen a head gasket fail on a M112 or M113 engine.

You sound like you have an overheating problem. If the temps are ok while driving but shoot up when you slow down then I would suspect that the viscous coupling is failing.

To test the viscous coupling with the engine cold, open the bonnet and then start the vehilce. Take the engine immediately to 2500rpm and hold it. The engine fan should be quite loud then dropping off after approx 10-15 seconds. If it isn't loud then replace the viscous coupling.
The aux fans can't keep the engine temps stable/down without the viscous coupling operating correctly.

Because of the tight engine bay then engines do run a high temp (relatively speaking). Seeing 95degC is quite normal so having a good radiator cap is crucial. If you have any doubts about the cap's ability to hold pressure then just change it. Remember, after shutdown that the coolant temp can rise another 10-20C above what it was shutdown at. If there is no pressure in the cooling system then you get localised boiling which will drump coolant out of the system.

If the thermostat was playing up then you would have either overcooling (not reaching 80C or frequent overheating (100C+) which you don't seem to be having.


As a side note I have seen a BMW dumping coolant with a perfectly functioning thermostat, coolant cap and radiator. The temp gauge would go to red then come a bit higher than normal. The water pump had plastic blades which had sheering off (no flow). The localised overheating was overpressurising the system and dumping the coolant. The low coolant level was fooling the temp sender into a false normal reading.

[SeeKlasse]

i really like how much mechanical expertise is accumulated in this forum, you guys really know your stuff!

[silence]

i wish i wasn't the one with the least knowledge- it seems in some respects i am the most "reckless"?

i'll be counting on you guys for a long time into the future

i can only hope that everyone shares the knowledge they have and i eventually am able to accomplish my real goals with this car.

[silence]

car is fixed- thermostat was all it was

[ob1kenobi]

Originally Posted by silence

car is fixed- thermostat was all it was

congratulations! I'm glad it was a simple one.