Over heating

[eddypeck]

Usually my wife take the car on short journeys, but this morning I took it up the motorway for 30 miles, and when I got off and got into traffic I noticed the temp gauge was at 3/4 and there was steam coming from under the bonnet.

Is this a sign of the viscous fan not working? and how can I test it, what other signs to look for. I'm not sure where the steam was coming from but was around the rad, while I was under the car doing the clutch I noticed a bit of furring around one of the bottom joints, it's possible the rad is leaking a bit.

[Gert_8]

coolant levels are okay, and the temp is in the normal range when it's moving along?

The viscous fan can be test with a rolled up newspaper. If it shreds it, its fine. If it doesn't and the fan stops, it needs changing, me thinks.

[eddypeck]

Coolant levels drop a bit, hence why I'm suspicious of the rad especially after seeing the corrosion on the bottom lip. Also I think the heater valve is weeping, not enough to dampen the carpet but you can see some corrosion around the seem.

Temp gets up to half way reasonably quickly and stays at half way.

[eddypeck]

Swapped the rad on the weekend, all seems well but temp gauge settles at just under half way now, I thought normal should be vertical? possible air lock still, or nothing to worry about?

[Gert_8]

From some of the threads I have read, I do not think that is anything to sorry about. Some owners claim the needle sits anywhere between the centre mark and between this and the next marker.

No doubt you will get some responses.

[Andyboy]

The viscous fan can be test with a rolled up newspaper. If it shreds it, its fine. If it doesn't and the fan stops, it needs changing, me thinks.

This old wives tale really should be put to bed now - it's absolute nonsense.

The viscous fan only kicks in when the engine is hot and in traffic/low speeds. You can hear it ( a higher pitched howl/drone) when it engages - a really good one will also engage from stone cold for a few seconds. When the fan locks, it's doing about 1500-2000 rpm at idle and the last thing you should be doing is trying to ram an old newspaper in there because a) you risk serious injury and b) you may well break a blade off the fan. Not great if it spears through the rad or your eye socket. If the car overheats at idle but cools down at speed, the fan is shagged. Any E30 still on the original will need a new one by now.


If it overheats on the motorway, the fan is not the issue. The fact that steam is coming out says that coolant is escaping somewhere, either past the rad cap seal as it boils its tits off, or from a split hose, knackered rad etc.

[Gert_8]

Thanks Andy - they showed the newspaper technique on TV! However, I totally agree it does sound a bit shabby.

[eddypeck]

Just to recap, was steaming because the radiator was knackered, it had a very small split in it. The Rad has now been replaced and the steaming has stopped.

Obviously in replacing the rad I had to replace all the coolant, and while the pipes were off I flushed through the system with a running hose to clear out as much of the cloudy brown water I could.

It took a little longer to get up to temp than I expected but once there was steady and didn't fluctuate.

So my question now is simply where should the needle point at normal operating temp? As in the picture it's currently sitting just before the half way mark and that was after a half hour trip up the motorway.

[JF008]

Mine used to be in the middle, changed rad, thermostat etc and now it sits one hair above. as long as its steady and between the marks near center its fine.

[Andyboy]

That's absolutely spot on. E30 gauges are pretty accurate - the new rad is flowing more coolant than the old one and doing a better job - hence why it runs a bit cooler.

[Mitchen]

I always thought it was the thermostat that determined where the needle was going to sit.. anywhere from the first level to the centre is normal.

[Brianmoooore]

The position of that needle is absolutely where it should be for an M40 engine, fitted with the correct 'stat. A M20 engine should haver a lower temp. 'stat, and the needle on those should be just past the first white mark.
As Andyboy says, the newspaper test is pointless. You can easily hear a fan that has locked on, especially if you rev. the engine.
The only time a car could overheat when stationary or in slow traffic, but be OK in normal running, and still have a working viscous coupling, is if there was a large 'cold spot', caused by blockage, in the part of the radiator that is directly in front of the centre of the coupling.

[Mitchen]

there was a large 'cold spot', caused by blockage, in the part of the radiator that is directly in front of the centre of the coupling.

How common is that?

[Brianmoooore]

Not common at all.

[eddypeck]

Thanks guys, seems like all is good and glad to see the needle is in the right place. It was at half way before with the old rad. Was worried perhaps I needed to change the stat too as had a similar issue with my mk2 golf where is ran cold as the stat wasn't opening fully.

[Brianmoooore]

One last point: Check that the coolant pressure cap is not the one it left the factory with, in case that is partly responsible for the leaking rad.
There was a safety recall to replace the caps in 1997, but many cars escaped it. Does your radiator bottle cap have a yellow disc on its underside?

[eddypeck]

The cap has a yellow bit, but there was another one in the boot so I was under the impression it had been replaced already. Also yellow on my breaker, so I have a choice of 3 yellow caps.... take it I need to get a blue one then.

[minesapint]

The cap has a yellow bit, but there was another one in the boot so I was under the impression it had been replaced already. Also yellow on my breaker, so I have a choice of 3 yellow caps.... take it I need to get a blue one then.

This may help with rad cap recall, read this.....

http://www.e30zone.net/e30zonewiki/inde ... g#Tank_Cap

And this......

http://www.e30zone.net/modules.php?name ... highlight=

Rad cap recall been covered before, only applicable to 1.4 bar cap. The press rating is stamped on the outside of the cap.

[Brianmoooore]

The caps with the yellow discs ARE the replacement ones, and should be fine. The original ones had a black base, but allegedly some replacement caps did as well.