Intermitant overheating problem
 

Hi,

I wonder if anyone can advise me of the likely cause(s) of this: on the way to work last week my water temp gauge went up to about two thirds which is clearly bad (its normally just below half way). About hlaf a mile later it went back down. Noticed that the coolant level was low when I checked, so topped it up. Everything was fine until this morning (although I have been topping up coolant every morning), the temp gauge has been going right up to nearly max and then going back to normal (it goes up in slow traffic and when I change to third with some boost it drops again). Checked the water and its fine.

Anyone any advice/ideas?

Darren

I would have said air in the cooling system

This page has lots of info in cooling and links to post with people experiencing similar symptoms to the one you describe


http://forums.nasioc.com/forums/show...hreadid=504002

I had exactly the same problem. Thought I was loosing water due o head gasket failure as was no sign what so ever for other water loss.
Had to top up water every week or maybe two. real slow rate of loss.
Turned out my radiator had gone with a real small hole in the top and was spraying a real small amount forwards into the bumper inside and hence could not see it.
May not be the same cause but had exactly the same temperature gauge activity when lower on water - sometimes even when water level looked pretty normal.

Yeah, think that could be the problem for me - found that when I got home tonight that there is a three inch crack in the black plastic bit on top of the radiator. I am having to top up the water at the moment about every 40 miles. New radiator then I guess, but wondering why this has suddenly happened and whether there is an underlying problem.

Any ideas best place to get a new radiator from (at a resonable price?)

i got one of ebay for about £60
it was completely the wrong size but works ok

I got mine from ebay also. Think it was about 80 quid but was the correct size :)

Story Update!
 

OK, so following advice on the thread "How to bleed the coolant system" posted on General Tech on the 29th, I have bleed the system as described. The hoses going into and out of the radiator were both full of air, but following this exercise are now both harder, so I assume full of water.

As for the crack in the plastic at the top of the radiator I have bonded that with a strong plastic glue (don't know if this will hold long term but worth a try, its withstood about 30 minutes of the engine running at temperature).

I am going to give the car a run out either later tonight or early tomorrow so will post back to let you know if its ok or not.

Darren