I know this is somewhat long but I want to accurately describe the situation.

 

 

I have a 1999 Subaru Forester with 165,000 miles and am having a problem with the temp gauge going into the red. This problem started today. Have not heard any strange noised or change in the car's operation. Just some hot coolant smell. The heater works. Here is the situation.

 

 

Last Thursday my repair shop replaced the timing belt, water pump, some tensioners etc. I did my 30 commute home that day and the next morning, most at highway speeds, with no problem. Friday afternoon after driving another 40 miles the upper hose from the radiator burst. This was the original hose. Finding no parts in the small town I was in, I had it towed to my regular repair shop. On Monday they replaced the upper and lower radiator hose.

 

No problem on my daily 30 mile each way commute until Thursday morning. About an hour after getting to work I had to leave for a meeting. When I went to the car I noticed a small amount of coolant under the car beneath the radiator. As I was parking the car after driving about 2 miles I noticed the temp gauge was almost into the red. After my meeting I drove it about a mile to the repair shop and the temp gauge was normal. The repair shop said it looked like there was some air in the system and that it blew out through the hose into the overflow tank. They said they ran the car for a few hours after topping off the coolant and the temp stayed normal.

 

I started to drive home but after driving about three miles it went into the red. I pulled over, waited for it to cool down then drove back to the repair shop. On the way there the temp gauge went up almost into the red, but while stopped at a light came back down to normal. By the time I drove through the intersection it went back up almost to the red. About a block from the repair shop it dropped back to normal.

 

The mechanic said it looks like air is getting into the system somewhere but he didn’t know where. He did check the coolant reservoir for combustibles which came up negative so he doesn’t think it is a head gasket.

 

Would appreciate any suggestions on what this might be. I tried to do a search of the board but didn’t find anything that fit.

Burst Radiator hose

Intermittent temp rise

Air getting in system

 

Cheap fix first, new radiator cap.

 

Expensive fix second , Head Gasket.

 

 

If the shop had introduced air in the system it would have happened as soon as you left the shop.

 

You dont check the coolant resevoir, you check the radiator itself.

 

Why all the work at 165,000 miles?

 

nipper

The thermostat may need to be changed out. It may be sticking.

If the thermostat doesn't help consider this

 

How about the condition of timing belt and components? If the belt is gazed it will slip over the smooth Water Pump pulley. Also if any of the tensioners are sticking it will cause uneven tension and slack in the belt causeing the belt to slip on the pump pulley as well. I have seen this a few times and I suspect it to be the cause of alot of folks overheating woes. People forget that the Water pump is driven off the T-belt.

 

EDIT: DUH!! I didn't read the whole original post. could still be related? perhaps the new belt has to "seat" on the new pulley? Did they replace the tensioner, and if so are you confident they did it correctly?

I agree with the shop, I think it is air. Wait until car is cold and take radiator cap off, then start car with heater on and add coolant every time a little is sucked in. Be patient and keep this up until themostart opens.