Overheating... still

[munky30]

Right.... my heap is still getting hot in traffic, and on occasion other times too.

On the way back from somewhere on the dual carriage way, doing a healthy 80mph it started to creep up the other day.

Eko was kind enough to give me a spare viscous fan the other day and benjy fitted it, but its made no difference.

It was 2nd hand so could well be a bit tired. After doing a bit of driving today when the car got a tad warm I tried the rolled up newspaper trick and the fan stopped fairly easily.

The overheating can be stopped by turning the heaters on full but as you can imagine thats not very nice in this weather.

Does the fact it stops with the heaters on mean its definitely the viscous? Or could it be something else... its been bled properly, but at this moment in time its just got water in it, no coolant, mainly because I am too tight to use it until I know I wont be loosing it all next time I have to do something to the cooling system. Once I know its all working fine I will use the good stuff.... unless that could be the cause of my problem? Is coolant that much more efficient than water?

[driftbmw]

try water pump
or
blockage in radiator

[cliffybabe]

id say bleed the system again mate

[munky30]

Have flushed through the radiator and its not blocked. Gets warm all over so its not that.

Surely if it was the water pump it would get really hot not just warm, and the heaters wouldnt fix it?

[march109]

are you 100% sure there is no airlock?

[munky30]

no... well, kind of...

Its been bled properly (run until warm, open bleed valve, wait until just water comes out, let it cool, repeat ad nauseum) and the heaters work, which I'm told means there's no airlock

[Alyman]

As far as I'm aware, there's a big difference between running a radiator system on plain water and on a proper coolant/water mix. About every six months my temp gauge will start to creep a bit over the half way point in traffic. I drain the whole lot and refill it with nice new stuff and it always seems to cure the problem.

As a bonus, coolant doesn't just raise the boiling point of water - it also lubricates the water pump and protects the water channels from corrosion.

[Brianmoooore]

Once a cooling system is bled, then it's bled. Any residual air will work its own way out.
Viscous fan isn't needed when the car is moving along freely, and water pump would affect the heater (E30 pump rotors don't normally fail, anyway).
If you're sure you don't have a damaged thermostat that doesn't open properly, then I would suspect the radiator, in spite of your tests.
AFAIK, anti freeze actually reduces the heat transferring abilities of water slightly, but is necessary at all times for all its other benefits

[munky30]

I've had the thermostat out to check that, was a few weeks back now but it worked ok.

Didnt think it was the pump as the effects of that are a lot more severe normally (they were on my old car anyway).

I know the viscous isnt working properly, but it still got hot that one time while driving at speed so it makes me think there's another reason... which I guess as you say, leaves the rad.

It sprung a very small leak a couple of weeks ago which now seems to have stopped (its not losing any water) so I got a facelift one to replace it with, along with a facelift water pump, expansion tank and hoses.

Went to put all that in last week and the metal part of the hose that runs across the front of the engine has nowhere to mount to. I know one of the bolts goes into the facelift water pump, but the other one didnt look like it could go anywhere on the pre facelift engine.

It looked like there should be a place on the cambelt cover for it.... does that sound about right?

Or is all that a waste of time and I'd be better off just getting a new pre facelift rad?

[spp320i]

to me (a relative novice!) this sounds like it IS your Viscous.

Other replies appear to have gone down other routes, but until you've got a viscous that works properly, I wouldn't spend the time looking for other possible causes. This is exactly how my car would behave, and I was sweating with the heaters on if I was stuck in traffic!

Definitely not an airlock - you get heat inside.

I suppose it could be the thermostat too, but if your viscous fan didn't eat the newspaper when it was getting hot, then it doesn't work as it should.

So change the viscous again, it's not that expensive, and definitely worth doing!

good luck, hope it helps!

[munky30]

I know the viscous is part of the cause, but that doesnt explain it getting warm the other day while doing 80mph.

[Jon_Bmw]

Spp320i that doesn't explain why it was getting hot at 80mph though. 80mph of wind over the Rad is far better than a brand new viscous fan could ever manage.

[munky30]

I'm also saying 80mph so as not to sound like a hooligan.. the speed was substantially more than that at times.

Now.. this may sound stupid, but the car had been being driven hard for most of the day, and I have a 316 diff so motorway cruising is done at around 4000rpm and a couple of times for short periods it had been nearer to the redline. I know people that use these as track cars and bounce them off the limiter all day long with no problems so I'd like to think when its sorted I would be able to do that too without worrying constantly about it going pop.

But.... Could it just have been getting warm in that situation as the engine is working hard?

I'm prepared to acccept that the overheating at low speed gentle driving is the fan.. but this time doing it at speed is a new symptom and one that worries me a lot.

[Martinaston]

If it overheats again check the small pipe from the back of the head to the internal heater, i've seen them blow steam when hot but run fine at lower temps. If it is that it will let air in and loose coolant but the header tank will still show a full tank as the airlock grows untill the steam pessure gets too much and it blows the hose clean off.
Sometimes you can see a few drops of water dripping onto the gearbox as the car cools down.
Other than that if you can't find a leak it could be the first signs that the heads about to go pop.

[1an]

i had this problem on mine. i rpelaced the thermostat etc but it stil over heated i replaced the radiator cap i nthe end and it seems to have sorted it self. have you replaced the radiator cap?

[munky30]

radiator cap?! I dont have one.... The only cap I have is on the header tank.

Ahh, you have a 316, the tank is on the rad.

Anywhooo..

I just ran it for a while stood still, let it get wamr, it didnt overheat, and the bottom hose from the rad got warm once it was up to temp so its not the thermostat.

BUT, the rad was cold down one side and hot on t'other. Last time I checked i guess I missed it

So... new rad and that should sort it... hopefully.

Martin, I've inspected every hose on it and they're all fine, cant see any leaks or splits, hot or cold, so I dont think its that.

[Martinaston]

Bottom hose will get warm just from the heat radiated from the block, if you watch the temp guage you can just see it drop slightly when the thermostat opens. Once its done that then check the rad because you know the coolant is circulating, if its still colder on one side of the rad then you probably need a new rad.
The filler cap should have a yellow centre on the underside with 140 on it. If not then get hold of one or it will over pressurize and blow the valve on the heater matrix.

[munky30]

It definitely got warm because of the water in it. Was stone cold then all of a sudden got warm.

It was after that happened, a few minutes after, that I checked the rad. I'm hoping that replacing it will solve the problems.

Not sure what cap I have... it came with the header tank. I have another facelift one though so may swap the cap from that one over onto the pre facelift tank?

[koos]

Hey Buddy, mine was pissing around the other day aswell, it turned out to be the gauge messing around, pulled out the cluster, tightened up the nut and all is well. Just a thought.

Mitch

[munky30]

my gauge is a whole different story... It starts at halfway when the car is cold, then moves up to the 3/4 mark for normal running temp. Oh and I have to tap it to get it to work when I turn the car on.

Apparently its either the temp sender or the si board causing it..,. neither of which are high on my list of fiddly annoying things to fix until after I stop it overheating.

[JohnnyThunders]

It definitely got warm because of the water in it. Was stone cold then all of a sudden got warm.

It was after that happened, a few minutes after, that I checked the rad. I'm hoping that replacing it will solve the problems.

Not sure what cap I have... it came with the header tank. I have another facelift one though so may swap the cap from that one over onto the pre facelift tank?

there was some issues with the header tank caps on facelift e30s i think, i had a problem with mine on the 320, rang the local BMW garage and they gave me a bag of four, free. "off" stock parts - apparently they were recalled, so may aswell get a new one even if is not part of the problem.

[munky30]

Its got a pre facelift one on it now, so I guess replacing it with the post facelift one is a bad idea.

I cant see how the cap would make it overheat though

[Simon13]

you need your temp guage to be working, you need to put coolant in it for a start, you need a working viscous fan.

lack of coolant f**ks the engine over in the end and results in head problems. Stop being tight and put your hand in your pocket.

how can anyone help if your not willing to anything yourself apart from fit secondhand sh!t thats as bad as whats been taken off? crazy

[munky30]

I was offered a free fan, figured it would be worth a try. I've just ordered a new one from bmw along with a new rad. Half the cars on this forum, probably more, are running on 'second hand sh*t'. If only everyone listened to you then no e30 in the land would ever have a problem

If I'd been pouring coolant in it for the last few weeks I would have poured about £50 of the stuff down the drain every time I take a hose off, check the thermostat, swap rads etc etc.

I know it damages it long term not having coolant in it but the car is getting minimal use at the moment for obvious reasons so I cant see it doing that much damage.

The temp gauge works, it just only uses the second half of the dial. So as its giving a reading that I can interpret then its low on my list. Stopping it overheating is a bit more important and I dont have the funds to do it all at once.

I dont have money to burn so if I can do something on the cheap I will try to, If that fails I will do it properly.

I have a family and not much money coming in, not that I need to justify myself to you. Why do you always try to bring it down to money? Are you that ignorant that you think everyone is in the position you are? Or is it just arrogance and the need to make yourself feel better than others by being richer than them?

[Dan318-is]

If the heating is hot then you can rule out an airleak. If you put a newspaper in and teh fan stopped then you can bet your bollocks to a barndance that needs replacing as well. The fact it overheats when its moving to can only be two things (both mentioned); either a blocked rad or a water pump. If it is anything else (could be a leak or a headgasket), il be suprised.

[HairyScreech]

just from experience with other stuff im thinking a lack of presure in the system, does the level go down but with no visable leaks?

if you can get a presure tester and pump it up, check for any obvious leaks and leave it for half an hour and then come back to it.

a lack of presure will lower the total heat capaity of the system as the fluid will be able to hold more heat when under presure (raises the boiling point a bit like how presure cookers work)

and on the antifreeze front the reason you shouldnt use water is because of the oxygen in it, it will begin to cause corosion in the block. antifreezes have corosion inhibiters in them to prevent this. at worst if you dont want to waste the coolant then boil the water first, this will reduce the oxygen content of the water. (oh and heat will speed a reaction up)

[Brianmoooore]

Too late in the day to read through the whole thread carefully, but I gather you don't have a correctly reading temp gauge. So what makes you think it's overheating?

[munky30]

Yes the temp gauge doesnt read as it should.

When i turn the key, and give it a tap, it goes straight to the middle line. Pointing upwards. Thats without the engine even running.

When the car has warmed up, it consistently sits at the 3/4 mark. Without fail.

After 10-15 minutes of driving it starts to creep up towards the red. I turn the heaters on at this point and it settles back down to the 3/4 mark. It really does seem like its compressed the whole gauge into the second half of the gauge... if you know what I mean...

[Brianmoooore]

I think it's possible that your car is running cool most of the time, and running it hard is just bringing it up to the correct temperature. Possible?
Should be simple (and cheap) enough to sort the gauge out.

[munky30]

Entirely possible I guess. But surely with a viscous thats not working right and a blocked rad its unlikely?

But Ok... how do I do that?

Its the SI board or the temp sender causing the problems iirc?

I swapped the temp sender today for one that worked fine on the old engine and it made no difference.

Si board batteries doesnt sound simple.. I cant solder, and replacing it isnt cheap. With my luck if I get one from a scrapper it will be worse and bmw charge a fortune for them.

(OT, you'll be pleased to hear that I finally got round to fixing the plug from the old loom onto the new loom for the oil pressure sensor today brian )

[jcjdavis1]

"Si board batteries doesnt sound simple.. I cant solder, and replacing it isnt cheap. With my luck if I get one from a scrapper it will be worse and bmw charge a fortune for them."

Hi Munky I had prob. with temp gauge and swapped with one I got from Breakers and it has sorted problem.I had to buy the whole clocks though to get the SI Board.

[Brianmoooore]

Try just removing the batteries from the SI board, if they are the AA sized NiCd ones.
(No idea if it will help or no, as I've never tried it).

[munky30]

Not replacing them?

Wont that stop my service indicator lights working? (no that I'm all that bothered about it tbh, would rather have a working temp gauge than si lights)

[Brianmoooore]

SI indicators won't work properly, but as things are going the engine won't last till the next service, so it's hardly relevant!

[munky30]

Thanks for the vote of confidence.

I should just give up now as obviously all my efforts to try and get it running right are a waste of time.