URGENT, Please help!

[firebat1986]

Hi guys and thanks in advance for taking time to help, as you always do. I'll try to make this quick.

I have a '91 toyota corolla. A few months ago I blew a head-gasket. After getting that fixed, my cars been running better than ever for about a month or 2 now. Today, however, I noticed something in my engine that is making me worry. I drove about 25 miles home from school and when i arrived home and turned off my engine, i noticed this spitting-bubbling sound coming from my engine. When I popped my hood i realized that the sound was coming from my coolant reservoir (the overflow). The coolant inside seemed to be boiling...

It's necessary for me to mention that when my car overheated months ago (when my head-gasket blew), i noticed that there was no coolant in the overflow and the hose actually melted to the overflow lid, closing the tunnel inside the lid which allows the coolant to leave the overflow.. I fixed the issue by cutting the part of the lid that melted (its the part under the cap, so that the lid still closed perfectly) so that I could blow into hole and feel the air coming out through the other end. I mention this, because, since the issue today seems to be coming from the coolant reservoir, i wonder if the coolant is not leaving the overflow. Could this be possible? Remember, that I've been running this car for a good couple months without any issues, although I don't use it very often..

Please send me any feedback you can. My hope is that what's happening is normal, although it sure didn't seem to be. Thanks again for any help you can offer, as I am not exactly a car-buff, and don't know very much about them.

Greg

[RogueMoog]

Seems to me that there's another issue at hand. Maybe the thermostat or a sensor is bad?

[bakwoods]

Quite honestly I'd start looking at you're thermostat. Did you replace that when it overheated?

Additionally, I'd say drain and refill the radiatorwhere as coolant boils at 250-275 degrees. Standard operating temperature of a car 185-205. If you get a thermostat and it's supposed to open up at say 185 degrees, then it'll get to operating temp and then open. Sometimes they open sooner, sometimes later. But usually between 185-200 they will come on. If the car is overheating, thermostat is going bad which will result in another blow headgasket. Avoid the headache by replacing the thermostat ASAP. For one, I assume the timing belt and water pump were serviced during the headgasket replacement? If not, then I say do it immediately. You can never be too careful. Fortunately, anyone with a Haynes manual, basic tools, and a few hours can do it.

If you lived here in NY I'd say come by my shop and I'd do it for you.

[firebat1986]

Thanks for your replies.. so you think it may be a thermostat issue? I've got an update.. just drove my car for about 10 minutes and kept a close eye on my temp gauge. It seemed to be getting a little hotter than it usually does, however it never seemed to get more than just a little above the middle line.. (usually its a little below)... Also, a short while after the incident, while the car was still a little war, when i started the car, something wasn't right.. It was kind of a slow start.. like the fan kept turning on and then off.. im not sure but it didn't seem right. After a few hours and the car is cooled off, it seemed to start fine.. Don't know if any of this info helps..

[bakwoods]

I have sneaking suspicion it's a thermostat issue. Problem is that without having the car it's hard to diagnose. I'm going off of my previous knowledge of what it "might be" and just tossing things out there.

It's not supposed to heat beyond below middle of the temp gauge, in fact, it should be just below the middle for normal operating temp. Anything above means that there is:

1. Air in the cooling system
2. Crappy coolant that is breaking down
3. Crappy thermostat
4. Bad water pump

A slow start is not really a symptom. If anything it sounds like an additional SEPERATE problem on itself. I know it sounds weird, but if it take more than a 3-5 seconds to turn on then start looking into other things, but lets not tackle that now.

The fan turning on and off is an indicator actually of the thermostat. The thermostat opens/closes at certain temps. If the car reaches a certain temp, the fan will turn on to try to cool the block. It usually doesn't help a lot but it's mostly for the exhaust manifold to divert heat from the block. I am still certain it's the thermostat or water pump, or BOTH even. Which is entirely possible.

The water pump in a car basically uses centrifugal force ie: timing belt, to pull water from the radiator and splash it, if you will, against the block for cooling. If it gets clogged, you'll get overheating issues. Since it is most likely associated with overheating issues, the thermostat is the next thing to replace with it.

I recommend swapping both out to be safe.

[Donald]

Make sure the radiator is full.
With the engine cold, make sure the coolant reservoir hose is below the level of the coolant, run the engine. If you are getting bubbles in the resorvoir, your head gasket is gone again, or you have a cracked or warped head.

Pull out the spark plugs (engine cold) and see if they are wet. If any are, blown head gasket, cracked or warped head.

Check your oil filler cap, if it is milky / coffee coloured..............You know... Blown head gasket, cracked or warped head.

[blb]

Originally Posted by Donald

Make sure the radiator is full.
With the engine cold, make sure the coolant reservoir hose is below the level of the coolant, run the engine. If you are getting bubbles in the resorvoir, your head gasket is gone again, or you have a cracked or warped head.

Pull out the spark plugs (engine cold) and see if they are wet. If any are, blown head gasket, cracked or warped head.

Check your oil filler cap, if it is milky / coffee coloured..............You know... Blown head gasket, cracked or warped head.

........X2

Donald is right on the money.

Also, when you look at the plugs, if any are extremely clean, chances are that cylinder is burning coolant due to a bad head gasket or cracked cylinder head.

[rdyzz]

make sure its burpt well. if you overfill your reservoir it will spit out whatever extra there is till its within a level it can use. this happened to me before, i was paranoid for quite some time till i found out that it was due to overfilling. your engine should use the coolant in the reservoire and spit it back out when the engines off.

[upnsmoke92]

Napa sells a coolant sniffer that I have had some luck with in the past, part # 7001006. A leakdown test can also be telling, if you have compressed air available.

[firebat1986]

wow, thank you so much for all your replies! Got a lot of good info to go off of.. There was someone who said to make sure your coolant resevoir isn't too full.. and i think mine is.. i didn't know that there could be too much coolant, so i put in as much as i could.. Speaking of which, 1 last thing: Is the coolant level in the resevoir supposed to get lower with use, because it seems to have stayed at the same level since it was fixed a few months ago. Shouldn't it be getting lower? Anyways, thanks again for everything!

Greg

[bakwoods]

Coolant reservoir is just an overflow tank. So if anything it'll stay the same for the most part.

Only reason I wasn't going with a blow gasket is because you said the gasket was repaired. I figured they milled the head and took care of that. If you had coolant and oil together mixing the car would be blowing blue/white smoke from the exhaust. Blue smoke = oil in the exhaust mixing = bad valve seals and coolant burning = white smoke getting into the head = warped head = coolant passages allow coolant to get into the block.

I would def start with plugs, but if it's running normally you wouldn't have compression issues, if he did then the car would bog down while hitting the gas due to plugs getting fouled.

I'd start by checking the plugs, then doing the leak down test, compression test lastly.

Who knows, it might be something simple.