Cooling PRT replacement

Hi All.

Thanks for all the help and the very informative "How to do" posts. As a result I changed the PRT on my 2003 MG TF this weekend.

After filling the system and bleeding it in the three places I ran the engine for a good 30 mins to check that the engine didn't over heat. All well so far, so I thought I would take it for a drive.

After about 4 miles the temp gauge started to above the point at which is was holding before (just below horizontal) and quite quickly.

I immediately stopped and only being about a mile from home I was going to wait and then nurse the car home once cooled. The previous week I was stranded on the M25!

After no more that 5 mins I decided to move (yes I was being impatience) but as I drove slowly the needle returned to just bellow the horizontal.

Checking the expansion tank when I got home the level had dropped a small amount (about 1 cm).

My question is do you think this increase in temperature was due to an air pocket and then when the PRT opened it flushed this out thus returning the engine temp to normal.

I'm very nervous at the moment driving the car until I'm 100% sure the problem is fixed.

Thanks

Simon

You ran the engine for 30 minutes. If that was largely at idle, there wouldn't have been a lot of circulation nor pressure. It is quite possible for some air to come out once the thermostat had cycled a few times but I cannot give a definitive answer. Nobody can. I can offer some ideas though.
Driving slowly the needle returned to normal. You have to mark the level cold, Take the car, warm it up, give it a brisk run and if the gauge goes up, expect HGF. If it doesn't, park it up where it was when you marked the tank and come back tomorrow. If the level is the same then you haven't got a problem.

Thanks for the reply.

I was told that the Head Gasket was changed only a few 100 miles ago so hopefully this will not be the problem.

Simon