Last night going up to the Mascrat Manor meet, my car started to overheat (went up to about 115 degrees) then temp went back down again. Also I had no heat from the erm... heater, despite having it set at 30 degrees.

At the meet I checked the rad... it needed some coolant, not loads, so I topped it up with water. On the way home it overheated bigtime. Temp guage was showing >140 degrees:eek: Just managed to get the car home in one piece. Undid the rad bleed screw, and much steam emerged:rolleyes:

This morning, filled it and bled it - drove to work, again no heat from the vents and again started to overheat.

Filled and bled it again and now its fine???

Needless to say, as I'm supposed to be driving to SE tomorrow, I'm somewhat concerned..... anyone got any idea?

change the stat.

Why should he change the stat??

 

 

Sounds like it needed bleeding!

because he doesnt give any indication of having any previous problems or having drained it recently.

Quite right, no recent problems at all.

Also the fact that I've got a cold heater makes me think it might be the thermostat.

Originally posted by AdamR

Quite right, no recent problems at all.

Also the fact that I've got a cold heater makes me think it might be the thermostat.

 

cold heaters has nothing to do with the stat unless it's jammed open but then you would see cold readings on your gauge.

 

sounds like an airlock to me. :)

 

Oh could be the HG. :D

I thought the thermostat when stuck closed, would cause the water temp to over heat but the heater will still work.

 

Adam, if you want I can try nip down to yours and help you fit a new one if you want? Either now. :eek: or early tomorrow. See if Halfords have one in.

 

Stuart

What you are discribing is what happened to mine. First of all the car started to over heat. It was fine one day and then over heating the next. It then just as quick started to not even warm up at all.

 

However I wasnt losing any water. But you could be losing some through the rad cap because its got so hot.

 

Stuart

Cheers for the offer Stuart, but I'm out tonight:rolleyes:

It seems to be ok at the moment so I'm gonna see what its like in the morning. Wish me luck....

Good luck. But if you want to change it tomorrow before you go, give me a shout if you need help.

 

Stuart

just take it out? if it cures the problem then u know its sticking.

The engine will never reach full operating temperature then. Which means always on choke and safty boost. Wont be good for MPG and considering he is going for a custom chip it will need to be working properly.

 

Also the oil will be cool and may never reach the temp where it works the best which means more engine wear.

 

Stuart

so when my thermostat fully opens, my engine cools down and i never reach full operating temp?????? i dont think so!!!!!

 

Of course it will reach its operating temp, it will just take a bit longer.

hmmm thinking about it.... as the engine cools cos the thrmostat is fully open, the thermostat will start to close and hence the engne will get a bit warmer again. hmmm

Originally posted by SRRAE

Also the oil will be cool and may never reach the temp where it works the best which means more engine wear.

 

The oil temp has a miniscule relationship to the water temp on a Zed!

 

The heater temp being cold has nothing to do with the thermostat if the engine is overheating!

 

The link between the heater core and the engine are permaneantly open with coolant constantly flowing around them.

 

The thermostat only when at the correct temp should open the cooling circuit, only to the radiatior and then include that in the loop!

 

If your engine was overheating and your rad was cold then I would blame the thermostat!

My solution would be to park the car on a steep incline, radiator highest and run the engine with the rad cap open!

Thermostats tend to fail in the open position more often than in the closed, think they are designed to do this, so that they dont blow engines.

 

If you have rust in system they can tend to fail when cold, but its unlikeley, id reckon this would oinly happen after letting the car stand for a long time.

 

Id wager its an airlock, but if not the cause may be more servere!!!

 

If you cant find any leaks on tickover it might be a good ida to give it a good hard rev on the spot, see if the increase in pressure causes any leaks.

 

I had to do this to discover my knackered water pump, on tickover and low revs it was fine, but rev it to 4 grand or over and the bottom of the pump would leak, only thing is you never see your engine when its reving at 4k as your in it, thus you dont spot the leak.

 

Oh , and Stu is dead right about the stat, if you try to run without it it will take hours as opposed to minuites to warm up, and also if youve got it stripped to the point of taking it out, you might aswell bung another in for a tenner!!

 

Good luck, hope its an easy fix.

I would agree with the thermostat when failing staying open, but this is exactly what happened to mine. My engine was getting rather hot and I thought it was the thermostat, but was told that they fail by staying open. Weeks later the engine never got to temperature even with over an hour of driving. A few more weeks later I changed the thermostat which was stuck open slightly, but in theory because my over heating had nothing to do with the thermostat, after I replaced it, it should start over heating again. It never has and actually only just gets to operating temperature.

 

When thermostats start to fail, they also react very slow and probably at the wrong temperature? Did any one see the video I made testing the new thermostat and the old one? The new one took 2 seconds to go from fully open to fully closed when dropped in cold water, the old one took over 2 mins. Same when placed in hot water. The new one opened fully in 2 secs the old one was slighly faster than before and opened in over a min. But in this min the water is getting hotter and hotter and the thermostat needs to open more but becuse it is slow it always behind.

 

Stuart.

Originally posted by SRRAE

Did any one see the video I made testing the new thermostat and the old one? .

 

Stuart.

 

LOL, How could we forget???;)

 

Accomanied by James Bond music too if i remember right!!:D ;)

Yeah.

 

I've lost it :cry:

ive got that vid if you want me to send it you stu.

Originally posted by SRRAE

Yeah.

 

I've lost it :cry:

 

We gathered that when you made that vid!!! lol

 

Ill check if ive got it, know i kept the strange and beautiful one as that was a work of art!!:)

Originally posted by Clarkey

ive got that vid if you want me to send it you stu.

 

Im sure I have the original somewhere. It was only for a laugh though ;).