Thermostat stuck closed???

Yeah, most likely what he said. It's a very cheap and easy fix.

DSMjrv said:

i have been having some heat issues with my car lately... and it seems to be that the overflow mechanism goes crazy as soon as the car gets to full normal temprature. then when it drains the whole coolant system the car starts to over heat.
...
i decide to gun it all the way up... soon as i shift into 3rd the heater starts actually blowing hot air full blast... and the needle, in the instant that the heater came on droped to the half marker on my engine temp guage.... like not even a second
whats going on?

Click to expand...

It sounds like your cooling system is not full and the water pump is cavitating at times. The fact you had no heat and then suddenly when climbing the hill water was forced into the heater core. This cooled and forced cooler water into the engine and dropped the temp down.

These cars are hard to bleed the cooling system, essentially you should remove the cap and run the engine until it gets hot and you you have plenty of hot air from the heater. Raise the rpm a few times to help purge the air bubbles from the heater core, keep adding water as needed.

Make sure the overflow tank is kept to the full level, watch the temp gage often. If it continues to pump water out the overflow then be suspect of a blown head gasket. Remember, your temp sensors/senders must be immersed in water to work properly, they will not work with air or steam in the system until it gets too hot and then there is the danger of frying the engine.

A stuck thermostat whether open or closed will not prevent heater operation, follow the hoses and you will see they are before the thermostat.

Cheers,
GTM

Replace the thermostat and the radiator cap. With luck, the overheating you've already done to the motor hasn't killed the head gasket.
Also, if your water pump had a plastic impeller, it may have lost its blades. Which will go into the water pump and timing belt job.

i already replaced both thermostat and cap. so that cant be the problem.

i filled her up completely full with water. turned her on, and the heater doesnt go. sat there and let it warm up, still nothing... turned her off took off the cap, i was only able to put like a cup of water in, so it was still full... overflow didnt go off yet... so i turn her on again and start driving around the block and still with no heater and the engine at normal temp i see a nice little trail of water coming out the right side of my car so i drive it still and the car starts getting hot and the water stops coming out....

i take it home, let it cool off... check the water... yup its prettymuch empty...


head gasket??? wouldnt i be able to notice a difference in the way it runs?

If your head gasket is bad and you are losing coolant your exhaust will steam bad. With the radiator cap off the cooland should bubble from exhaust being forced out. Or if it's really bad like this explorer I saw a while back the coolant will shoot out like old faithful.
I think I would refill it and take your time and follow GTMs instructions.
Are you filling it on a flat area or is the car pointing up, down or on an angle side to side? That could make a difference in trapping an air bubble somewhere.

wait a sec...certain cars came stock with plastic water pump impeller blades?

i just did a water pump job on 90 Galant GSX 4g63 n/a awd

everything was metal - i never saw a plastic one?

yoshimitsuspeed said:

...
I think I would refill it and take your time and follow GTMs instructions.
Are you filling it on a flat area or is the car pointing up, down or on an angle side to side? That could make a difference in trapping an air bubble somewhere.

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If you look where the heater hoses pass through the firewall you will note they are as high if not higher than the highest point of the cooling system. (not uncommon for a lot of cars) This is the perfect place for air to get trapped and will will not be forced out until the RPM has been increased several times. If you have the heater set to max and the fan on low to medium speed you MUST get heat or you have not filled the system. (provided you don't have something wrong there... which you seemingly don't) Now there are ways of helping this along such as adding a fitting in the hose so you can attach a garden hose and force the air out but not always effective and it will dilute antifreeze. Since freezing isn't an issue where you are I wouldn't worry about that until you get this problem under control.

If you can find a good incline or put the car on ramps it will make a big difference in purging that trapped air in the heater circuit. You can't rely on steam coming out the exhaust when diagnosing a blown head gasket though if the engine and exhaust is properly hot and you see it then you could have reasonable suspicions.

The trickle you see driving down the road can be from the trapped air expanding as it sees some hot water flowing through the heater core thus building pressure so that to is not an absolute. You will get plenty of opinions some accurate and some from snap judgments not based on solid information. Nor is seeing bubbles in the cooling system for water pumps can cavitate and suck air into the system and yet NOT leak fluid. All this being said your best bet is to get a "block check" (which can be a misnomer) if you are checking for a blown head gasket. You may be able to rent a tool for checking from Auto Zone, if not then find a shop who can check this for you, or buy the tool.

My seat of pants gut feeling now is you do in fact have a blown head gasket and you should start making preperations for this. I think it's in the early stages and you can't feel the loss of power but you must modify your driving habits so you don't destroy the engine and be faced with $1000-$2000 in repairs. Baby it, don't accelerate hard or fast, don't lug it, avoid freeway anything, however, if it's a must keep the speed to 50-55, keep 2-3 gallons of water with you, check often. If you loose the heater then you don't have enough water in the system. You can also try retorquing the head bolts to the high end of specifications BUT do not exceed more than 10%. When a head warps from overheating it also affects the camshafts so you don't want to end up with a piece of junk even if the cylrs are good.

Sorry to be the bearer of not so good news but better to know now than later while you still have a chance to save it and your wallet some pain.

Cheers,
GTM

that post just brought a tear to my eye

good stuff!!!

okay... my headgasket it blown...

i had some mexican mecanic check it out, i met him at the gas station and he was pretty cool... so he was looking at it and checkin stuff out and said it was blown... and well its runnin pretty ruff too so i figured thats gotta be it...

even with a blown gasket, shouldnt it maintain temprature? assuming everything in the cooling system is fine? or is the blown gasket causing my system to purge all of its water and thats the reason its overheating...

um how much does it cost to replace? like just the head gasket not replacing any valves and whatnot? and can i do it myself? is there some online tutorial on how it can be done? how much would it cost just for parts? how many hours of work?

btw thanks for the help

DSMjrv said:

even with a blown gasket, shouldnt it maintain temprature? assuming everything in the cooling system is fine? or is the blown gasket causing my system to purge all of its water and thats the reason its overheating...

Click to expand...

Not if combustion chamber gases are pumping into the coolant.

unior said:

wait a sec...certain cars came stock with plastic water pump impeller blades?

i just did a water pump job on 90 Galant GSX 4g63 n/a awd

everything was metal - i never saw a plastic one?

Click to expand...

Some after-market pumps had plastic impellers.
http://www.dsmtuners.com/forums/showthread.php?t=151759

DSMjrv said:

okay... my headgasket it blown...

um how much does it cost to replace? like just the head gasket not replacing any valves and whatnot? and can i do it myself? is there some online tutorial on how it can be done? how much would it cost just for parts? how many hours of work?

Click to expand...

i *think HGs are about $80 from satan. check the flatness of the head with a metal shop rule and a 0.002" feeler gauge. do it on diagonal Xes, down each side, around all oil and coolant holes, and right down the middle. as long as you can't fit the feeler under the shop rule, you're head is fine.

pulling the head is pretty easy, but a PITA. i'm not aware of an online tutorial, but check the vfaq.

here's my advice... leave both manifolds on, but unbolt the turbo and hang it with some shoestrings/rope, etc. make sure you loosen the head bolts in the proper order. get a friend or cheery picker (if available) to help you pick up the head/mani combo... it'll be pretty heavy and awkward. you're going to have to undo all the coolant lines, throttle cables, CAS, coil pack, power transistor...etc. get some copper spray to put on both sides of the new HG and make sure you keep the mating surfaces CLEAN. Conservatively, give yourself a weekend to get everything done. Also, if you change head bolts to ARPs, check the torque after a few hundred miles to make sure everything is OK.

It's also a good oppertunity to change your timing belt and tensioners, water pump, ect if your any where near due.