Anyone got an idea of what to do next?
 

Problem first noticed in April. My car will heat up normally but the heater blows cold air...then it would go normal then cooler then normal etc. I did nothing as it wasn't a big deal. Then I noticed a few weeks later that it was blowing cold air but the temp gage was showing it was starting to over heat, I got ready to pull over and stop and suddenly the temp gage went back to normal. No problem again for 3 weeks then the above repeated. Now move to Monday of this week, it was hot out over 90 and my air was not blowing cold air but cool air and the temp gage once again did it's up and down thing. So off to the dealer. Yesterday they put in a new thermostat, flushed the cooling system and the freon in the air. All seemed well nice real cold air, then tonight it did the temp gage thing again up then down. I cranked the temp in the car as high as it goes to see if I got hot air from the heater, no hot air?

The rad and the condenser are two years old, the water pump in 8 months old and the thermostat is new and everything has been flushed. No error codes on the climate control. What is left to check? Could my heater core be the problem as it is original so it is from 1992 and the car has 375,000 km on it. Does anyone have any idea's as to where to start to look for the answer to this problem? Yesterdays trip to the dealer cost me $350.00, I don't mind spending the money if it results in a solution, any help or ideas would be greatly appreciated.

air bubble
 

It sounds like you probably have an air pocket in the system.Not 100% on the bleeding procedure but when i did my radiator i just ran the car with the cap off till water came out of it and there were no air bubbles... when the car is hot, touch the heater core hoses with the heat on. are they hot?

Also run the normal checks for either a cracked head or bad headgasket. Sounds like a headgasket.

How can I tell if it is a blown head gasket? Would it be weeks between problems if this was the case? Would I see smoke or something coming from my tail pipes, there is nothing coming out of mine.
I just went out and removed the radiator cap, there was no coolant to be seen!
Yet the overflow reservoir is full? This was just flushed and refilled yesterday at the dealer. Should I not see fluid when I remove the cap?

Guess it's back to the dealer tomorrow :confused:

You are supposed to see fluid when you remove the cap. It seems exhaust may be venting into the coolant system and blowing the coolant out the overflow.

If you run with the rad cap loose you should keep your coolant.

it sounds like the dealer didn't take care to burp the system

Head gasket.:( My van does the EXACT same thing. Sounds like it isn't to bad yet so try one of the block sealer products out there(bars leak) and it may just fix you right up for a little while longer. Good luck.

are we really sure on this one i mean are there more tell tall signs like coolent goo under the oil cap or oil in the coolent... issuses like sudden studdering... or maybe there is just a leak in the coolent system

are you loosing coolant? white smoke out of the tailpipe?

Not if it isn't to bad yet. My van had no signs at all for the first few months other than the temp gauge would stay cool and bounce up every now and again going down the highway and when idling for a minute and the heat would go in and out. Then it got bad and start showing all the typical signs. I got it to stop leak for about 3 weeks and everything worked great and ran great,then it blew out and got worse.

There is a test
 

Some garages will have a testing unit. They can take a sample of the coolant and determine if it has been exposed to exhaust fumes. The test takes only a minute or two.

Thanks guys for all your idea's. I'm off to the dealer to see what they have to say, I'll post results.

I would say try and bypass the heater core to see if cures your problems. surprisingly enough, it has happened before where the coolant will voerheat because of a blockage like this. Don't automatically think HG try the little things first before you spend a ton of dough getting a HG replaced that didn't need to be

Tom

Here's an update. I drove to my Subaru Dealer (same one I bought the car from in 1992, I have the same mechanic since day one) leaving the rad the same as it was last night, no coolant showing and the overflo full.
My mechanic saw me as I drove in and came immediately to me, I explained my problem and he told me to drive it right in to one of the service bays.

He refilled the rad, pumped out the extra coolant from the overflo and put on a new rad cap. He put a light beside the overflo and started to rev the engine while watching it. He saw nothing in the 3 or 4 minutes he did it for. He told me I just don't have the right symtoms for a blown HG, but anything was possible.

I drove the 65km to work, let it cool off and then went out to the parking lot to check it out. I removed the rad cap and it was full to the top, the overflo was exactly where it should be. I have just driven home and all coolant is exactly where it should be?

So, I'm..... at a loss for words as I wait to see if the problem is solved or I'm in for a major repair. Talking about repair, a guy at the office told me about this stuff from rxauto.com, thermogasket or something. It sounds too good to be true...comments?

Again, thanks for all the feedback.

It could have been an air pocket in the system, keep a close eye on the temp gauge and fluid levels if they are all stable for the next few days you should be good.