Motorway Overheating.

[yellowmellow]

MY E30 (eta) is overheating speed on motorways, I thought this was a bit strange with the amount of air going in the front !

Anyway this must mean something else is afoot. Sometimes it does go close the red around town- but can be made to drop by turning heater up full blast. coolant does need topping up now and then Would I by right to think ;-

air block- thermo- water pump oh oh !!!

happy for any help

[Brianmoooore]

A new radiator would probably solve your problems, if you're running the original.

[psychochild187]

or a leaky hose somewhere.
eg the small one on the bottom of the thermostat housing.

[yellowmellow]

Thanks for you quick replies chaps,

I just noticed with my Bentley manual in hand that my high speed fan relay was missing from my fuses box. I,ve put another one in now. But I will also check the rad and hoses.

Cheers and THANKS again,

[Cypriotgeeza]

At motorway speeds, you should not need any fan to cool the engine. If this is the only time you experience overheating, then, as Brian says, it is most likely your radiator that is at fault.

either that or maybe your water pumps so knackered it cant keep up with the demand it needs to pump..I've seen that before on a few cars!

[magpie]

is the pass side carpet wet?and if you've had a large top up of coolant have you bled the system?

try letting it tick over and look for leaks on the ground.

[psychochild187]

high speed fan relay .?
but the radiator fan is mechanical. and not electrical

[Cypriotgeeza]

high speed fan relay .?
but the radiator fan is mechanical. and not electrical

yea probably why it was "missing"

[12345kevin]

Had exactly the same problem with mine, high speed or long hills brought the temp up. Change of Rad cured it

[bmw9818]

check your water pump my one was so knackered the fins had completely worn, there was literally nothing left!

[clipper]

Had exactly the same problem with mine, high speed or long hills brought the temp up. Change of Rad cured it

Having exactly this issue at the moment.

Yesterday I poured a bottle of nitric acid into the radiator (out of the car) to see if I could unblock it, seemed to be an agressive cleaner .
I'll let you know if it has worked when I get it back together....

[bimanut]

Hope you`ve flushed it well!

[clipper]

Hope you`ve flushed it well!

Flushed it with fresh water before fitting it back in the car, now the coolant circuit has some flushing additive in fresh water, so if any did remain it will be extremely diluted by now.

SHould be OK.

[yellowmellow]

Cheer,s to all the above for your help,

I reckon it must be Rad or water pump then as I,m showing no Leak,s and no damp carpet.
Wondering what that relay is for and why it was missing (according to Bentley manual )anyway.
I wonder if a mild rad flush could help or sod it i.ll do them both..
Thank,s again geezers!

[yellowmellow]

yeah clipper let me know how it goes

[clipper]

Well, yesterday I bled the system properly and let the car heat up with the rad flush in there.

I had previously used a good quality rad flush and it had left what seems like a large amount of crud in the rad. I think they're OK for general use, but for cleaning a rad after a H/G failure they don't seem to be strong enough.

The only problem I noticed now is that the gauge was very slightly over half way when the thermostat opened. I took it out and it has 80º stamped on it, but in a pan of water it wasn't fully open until the water was boiling. I doubt that this was caused by the nitric acid though, the radiator seems to have survived that attack rather well.

In order to eliminate the causes I will put the same thermostat back in and run the car on the motorway to test if the radiator acid attack has helped, if that doesn't work I'll try a new 'stat.

Assuming one of the above fixes it, I'll let you know.

[clipper]

One last comment.

If in doubt, do what Brianmooore says.

I bet you that in less than a month I end up doing exactly that anyway..... but it's good fun trying to find ways around spending money on stuff.

[clipper]

Didn't work.

New radiator time !

[yellowmellow]

Yes clipper-

I think that,s going to be the way to go mate, I,ll do the water pump -timing belt- thermo at the same time so it job done.
By the way mate, do you know where the engine number is on the actual engine as this eta engine of mine was put in by my mate and all I know is it,s a 1985 (525) I think there was two out that year. I know need that info to by parts.

cheer,s pal

[jmc330i]

high speed fan relay .?
but the radiator fan is mechanical. and not electrical

yea probably why it was "missing"

E30s with aircon have electric 2 speed fans (low and high speed) as well as the viscous fan. The manual will cover most spec of cars so will show the extras.

[clipper]

Just had one last attempt at unblocking my rad.

This time I filled it with caustic soda...... now I have stains on the balcony tiling and a hole in the rad !!!

I think I'll leave it now and buy a new one

[bobbin1982]

well if it wasnt broke.. it is now

[Brianmoooore]

Caustic soda reacts violently with aluminium. Explosively under certain circumstances!!

[clipper]

Caustic soda reacts violently with aluminium. Explosively under certain circumstances!!

It's pretty tough on terracota too.

[octanejunkie]

Good for de-coking 2 stroke exhausts though!

[yellowmellow]

AAAArgh IT WAS THE WATER PUMP> IT WAS THE WATER PUMP> IT WAS WATER PUMP. After changing
thermostat and viscous I was just about to do the rad, mate said pump, I owe him a drink !

[Brianmoooore]

What exactly was wrong with it?
A new rad will still be a good investment, if the one fitted is the original.

[yellowmellow]

Yes brianmooore,
Sorry for late reply, The water pump had loose bearings , (If they are actually bearings) it grinded and rumbled a bit as I turned it in my hands, also it had a couple of millimetres of play too, new one turned sweet and quiet. The needle sits mid way now instead of charging towards the red. Shazz325sport sorted me out neatly since a certain dealer sold me the wrong pump shazz had a spare.( we had all ready pulled knacered old one out). I may still change rad, but I may be going for a 3.5 lump. What do you think of them. And thanks for you help and every one esle too.

[town325i]

3.5 lump. What do you think of them. And thanks for you help and every one esle too.

Please do a search on this rather than having pages of Rav bleating on about how good an M30 boat anchor is

[Rav335uk]

3.5 lump. What do you think of them. And thanks for you help and every one esle too.

Please do a search on this rather than having pages of Rav bleating on about how good an M30 boat anchor is

Ignore the hater above, always talks S h i t.
Any info you need on the M30 can be found in the engine swaps section, or just ask.

[Brianmoooore]

Any info you need on the M30 can be found in the engine swaps section,

Right next to the M50/52 forum!

[Rav335uk]

Any info you need on the M30 can be found in the engine swaps section,

Right next to the M50/52 forum!

Brian, he was asking of going M30, not plastic coated engines.

[town325i]

Any info you need on the M30 can be found in the engine swaps section,

Right next to the M50/52 forum!

Brian, he was asking of going M30, not plastic coated engines.

See look even the very wise knows the better engine There will be less plastic on my car than ures even when i have the m50 in the bay

[Rav335uk]

No SPAMMING !!