E30 Zone

hi guys,
got the car running finally and have found a problem. Now that the temperature gauge is fixed i have found out that the car is overheating.

When started, it gets up to temperature in about 10-15 mins. After another 10 mins or so the temp starts to creep slowly higher. It has got to the 3 quarter mark and by this time I shut it off to prevent any damage. I have tried starting the car with the expansion tank cap off, and with the blowers on full, to remove any air locks, but it still overheats.

What could be the problem? fan not working properly? because i havent attached the shroud? faulty water pump? the dreaded head gasket or even worse, cracked block?

Any help is appreciated,
thanks,
josh

3/4 mark is not overheating and is fine as long as it heads back down once on the move. If it starts going over 3/4 and heads towards the red I'd be worrying.

Lack of fan shroud won't be helping when the car is stationary. Is the rad in good condition? - the rad is actually a service item.
A thermostat is cheap enough and could be worth changing if its old and not opening effectively.

after the 3/4 mark the coolant starts to boil and overflows from the tank. If the system is under pressure wont something burst when the coolant rapidly expands?
Are you saying that i need a shroud or it doesnt matter?
As far as i know the rad is in good condition, no leaks.
And also the thermostat is ok because the bottom pipe stays cold until the engine reaches temperature, then it starts to heat up, indicating that the thermostat has opened and is trying to cool the engine.

After the 3/4 mark or when the needle is in the red?

The rad might look ok, not leak etc, but they can partially block meaning it won't cool properly. The thermostat might open, but it might not open soon enough or wide enough. On my M40, the stat seemed to work when given the boiling water test in the kitchen, but a new one sorted the cooling issues I had.

The fan shroud is there for a reason, the lack of one fitted will not be helping as the fan is able to pull air from around the rad rather than just through it.

if the coolant is boiling up that easily then the system is not pressurising.....

I think that the fact the coolant system should be under pressure will stop the boiling. The water can get up to higher temperature without turning in to a gas when it is under high pressures.

sorry, no it wasn't pressurized because i left the cap off.
i found out that the boiling temp rises when under pressure so i gave it a bit more of a chance to level out in temp.

so i tried idling the car outside for 15 mins, it rose just above the 3/4 mark and then cooled down to the half mark again. after 10 more mins of idling, when i drove the car back in the garage it heated up so much that the top pipe blew off the radiator.

Im not sure if there was an air lock in the system, or gas leaking into the system, or water leaking into the block. i guess that if it was an air lock, the coolant would replace the air and thus the tank level would drop.

sorry, i didnt see your post above, but thats what i was thinking.

Would you be able to test the flow on your rad? I've got a good, working rad here from an m40 you can have for cheap if you think that may be an option.

There's no reason a properly functioning m40 should go over half. In the height of summer, at santa pod, my m40 got just below 3/4 on the gauge. This was after many runs down the strip, and it only got hot when sitting in the traffic waiting for the next run. As soon as it went on the strip it got down to half (had 18 seconds to cool down going down the strip lol!)

I think that the viscous fan was knackered though.

if there is a problem with my radiator then i would definitely be interested, thanks.
As much as i hate to say it though, i think the problem is deeper than a thermostat, fan or radiator. i am beginning to think that the gasket has gone or the block is cracked.
can you explain steam coming from the exhaust when the engine gets slightly warm?

if there's steam coming from the exhaust I would say its your head gasket. also if there's enough pressure to blow the top hose of there is a serious issue there IMO

josh-uk wrote:if there is a problem with my radiator then i would definitely be interested, thanks.
As much as i hate to say it though, i think the problem is deeper than a thermostat, fan or radiator. i am beginning to think that the gasket has gone or the block is cracked.
can you explain steam coming from the exhaust when the engine gets slightly warm?

Could you do a compression test?

possibly, i would have to borrow a tester though.

whereabouts are you?

Ok, having read through the replies, I saw that you do not mention when you have started it, is it parked? or being driven?

Just to add to ravs question, how long didn't the temp guage work for and did the car get driven while it.wasn't working?

The car isnt being driven, and hasnt been driven since september (when i bought it), before that it had been standing for a while.
Im not sure how long the temp gauge hasnt been working for as i bought it like that. I found the sender unplugged which is suspicious! i was aware at the time that it may have been unplugged to hide the fact that it is overheating.

Could be your Viscous fan then not working properly.

check the belt is tight, roll up a newspaper and see if the fan shreds it,

if not m40 head gaskets no biggy! heads are cheap enough and easy to come by, ive got one from my old one laying around

you can have the head off in about a day,

I would say the viscous fan, mine did the same until I changed it, now it simply doesn't go over half!...I did have difficulty getting the nut undone, ended up changing the water pump (where the viscous fan is attached) as I didn't want any part of the cooling system to be at risk of failing (went around france in summer for a while). If you do the water pump and viscous fan, do the thermostat too to eliminate that, it's cheap enough!