Head problems?

[speedymacfish]

Do i have a problem?
I've just picked up my surf and noticed it's over heating in traffic and when idleing. I have filled up the water overflow a few times now, is there any other reason for this? If i up the rev's to around 3000 it cools off, but rises again when left to idle!

[marky]

are you filling water bottle to the top

[Koi]

Do i have a problem?
I've just picked up my surf and noticed it's over heating in traffic and when idleing. I have filled up the water overflow a few times now, is there any other reason for this? If i up the rev's to around 3000 it cools off, but rises again when left to idle!

HI,
First off stop filling the overflow/expansion tank up. You should fill through the rad cap on top of the engine, the expansion bottle should only hold about an 1" or so of water. As the engine gets hot the water expands into this bottle and as it cools pulls it back in to the engine.

Now your overheating could be down to an air lock, that, only when the water pumps at a higher rpm it moves the water.
Or could be the viscous fan not working on tick over and only picking up at a higher rpm and actually doing anything. Check the fan first for correct operation.

[robnw67]

Something in the water

I had a similar problem to this with my Surf following a mate playing with the rear heater control. I had an airlock in the rear heater matrix which my mate accidentally cleared for me. However, coupled with this, I also had a leaking pipe at the top of the expansion tank. So the hot engine pushed out coolant and then just sucked in air as it cooled down.

With low coolant in the system, the gauge ran hot and cold depending on engine speed.

I had to run the car hot with both heaters set to the hot position. Then after it cooled down, top up the water at the radiator cap. This made sure the system was as full as it could be. Then I replaced the leaking pipe at the expansion tank and again checked the level.

Might work for you. Of course - it might just be a dodgy cylinder head..........!

[da SLUG man]

does it cool as you rev it?
i.e you can noticably see the needle go down?

could be low water pressure not pushing the thermostat back on the spring
or the regulator on the alternator not popping out the correct voltage so you get various readings as the current from the sender changes...

but hey,
i learned my mech skills on a qualcast suffolk puch lawnmower and then advanced to a mini... so don't believe a word i say!
to be honest i've only looked under my bonnet twice on the surf!
too many electric bits that have an unexplained purpose!

[high-surfer]

Another thing you could look at is the auxilary electric fan. This is situated in front of the rad on the off-side.

Ian