Driving along last night with the front screen misted up as usual (had to wipe with a cloth three times in 15 miles) and the temp was on freezing even though the temp was set to the top!

 

When I joined the dual carriagway and hammered it upto about 85 the temperature raised again. When I slowed down it was cold again. On the return journey it was up and down all over the place.

 

Any ideas

 

Ivan:mad: :eek:

You checked the coolant level recently?

 

My money's on lo-water level, then perhaps an air lock, but check the level first.

 

Tim

Yeah topped coolant up last saturday from very low.

 

Ivan

Air lock then.

 

Had it been a long time between top ups?

 

Tim

Provided your water level is right and you dont have a gassing blown head gasket causing airlocks it sounds more like a dead thermostat. These are designed to fail open. This means your engine is over cooled instead of the other. To prove it start it from cold let it idle and feel the top rubber hose connection. Watch your fingers with the fan mind! If it warms slowly the hose will gradually get warm but never hot - means that coolant is flowing from word go instead of being held back until proper temp reached. If the thermostat is working properly it would stay stone cold until the stat opens whereupon the top hose suddenly hots up as hot water is allowed to circulate to the radiator at the correct running temp. Your guage should also show low temp all the time when the stat is jammed open. Also no heater! You'd probably need 25C outside and slow traffic just to get it up to normal with a jammed open stat! or go at 120mph or more!

 

If your water level was low or you had an airlock with no circulation- driving hard would totally sh*g your engine, warp heads blow head gaskets etc and your heater would still be cool.

 

A temporary if dodgy fix if its thermostat is to put in a sheet of cardboard to cover at least half of your radiator surface. Its trial and error. Never tried this on a zed though. This helps reduce the cooling available and brings the running temp up a bit till you get a new stat in to regulate it properly. You have to watch temp carefully! Running cold all the time is also not good for it.

Willie

No, not running cold all the time, After about 3-4 miles the temp guage shoots up to normal conditions. I've not topped it up for as long as I own it (6 weeks) but it was low when I bought it. Don't know how long it was low before I bought it.

 

I do know that it had a re-con engine 5,000 miles ago. And there is some water in the footwells but I thought this was when I washed it and water got down in the scuttle panel. It's not losing any water on the garage floor.

 

I did think about the thermostat so this could be the problem. I don't drive it hard all the time just accelerate hard for a short time occasionally but don't drive it very fast (no more than 85 on dual carriageways) and I only drive 2-3 times a week.

 

It's going into Jeffs in a week for some work so mabye I'll get him to have a look into the problem.

 

Ivan

:D

Did you have your heater on?

 

I notice if I drive at night with the heater on trickle it cools the engine quite a lot. Normally the needle for the temp sits in the middle and never moves. Even when sat in traffic for an hour in the blistering heat of the summer, it stayed in the middle. But driving with the heater on, even when its on low, dropped thed temperature to 1/4 on the dial.

 

Stuart

Yeah, had the heater on but there was no heat! The temperature needle was in the middle of the guage. Don't know about the hot day thing as I've only had it in the cold weather!

 

Ivan