Engine Overheat - Do symptoms include Power Loss?

[HertsPete]

Hi,

I've had a good read on the forum & think I've tracked down the cause of a problem my van's got. I just wanted to do a quick check and confirm if I can.

My van's a 1989 T25 Water cooled petrol.

Just recently she's starting losing power but only when the engine is hot. The engine seems to run very hot and while running her on the driveway the engine fan will sometimes kick in (only just about I think, but it does). I'm thinking the engine is overheating, which some posts say will cause power loss.

Is that right? (i.e. overheating would cause engine power loss)
Does it sound like I'm on the right track?

I've a feeling I may have air bubbles in the coolant system & may need to bleed it.

Any thoughts appreciated

Thanks

Peter

[Ian Hulley]

I've a feeling I may have air bubbles in the coolant system & may need to bleed it.

Pete I think you may have answered your own question. Bleed the system and then see where you are.

Ian

[syncrosimon]

When tinkering with the engine when stationary the front fan will come on from time to time. Some seem to rapid cycle ie come on regularly for short burst's, whilst mine comes on less frequently for longer periods. The fan is very powerful and you will know when it's on, but it is sometimes hard to hear when you are staring at the engine and the tangle of pipes and wires. The temp gauge if working correctly should sit somewhere near the red dot in the vertical position, and once warmed up should stay fairly local to that dot, if you have a lot of movement then it may indicate a problem.

In this cold weather the interior heater matrix can just about cool the engine on it's own, when pootling about. I have driven 9 miles and the front radiator is not hot, so if the needle is going up, switch on the interior heat. If this causes the needle to drop, then it indicates a blocked inefficient radiator.