Sorry....Overheating

Post Mon Oct 03, 2005 9:01 am

hello all Zoners....

I'm just abt to pull my hair out so please can someone help before i have no hair left....

the water pump went, bearling making a funny noise...got that changed alongside the thermostat.... now she just seems to overheat.... straight up to the half way point and lingers there for abt a min then off she goes into the red zone.....temperature needle that is...

both sides of the radiator pipes are extremely hot...shuoldnt one be cold?

another thing the viscous isnt - well doesnt seem to be 'kicking-in' with all this outrageous act.....also im getting cold air from the car heaters on any heat setting....

help....pls.....

Post Mon Oct 03, 2005 9:14 am

think u could have air trapped in system, may just need to be bleed

Post Mon Oct 03, 2005 9:18 am

if the viscous is not turning on tickover than that is your first problem, so I would look at replacing the viscous, think they are about Ãƒ”šÃ‚£30. Would also check your thermostat and look at changing that. You may have got an air lock in your system when you dropped the coolant to change the water pump. Maybe's worth trying to bleed the system again and topping it back up but make sure you have the heater set to max when doing this and the fan on a low setting.

That may sort your problem by process of elimination, maybe some other zoners have some more ideas? Or will put me right where I have stated anything incorrect

Post Mon Oct 03, 2005 9:26 am

You have an airlock in the heater circuit.
GET IT SORTED before you crack the head.
Park the car with the front end higher than the back, fill the coolant resevoir to the brim, undo the hoseclip to the top heater hose (on the bulkhead) and pull the hose just off the spigot to allow any air to escape.
Put the hose back on, ensure the heater is set to full hot and start the car. Ensure the heater is beginning to produce warm air as the ytemp gauge moves of its stop.
Next release any air at the front of the engine by unscrewing the thermostat elbow bleed.
It will take a week to get all traces of air out of the system.

Post Mon Oct 03, 2005 11:41 am

is the air lock causing it to overheat???

Post Mon Oct 03, 2005 2:07 pm

yes, because there's possibly no coolant circulating around the water jacket in the head, so it cooks itself. Because the block is iron and the head alloy, they expand and contract at different rates and this is how you will crack your head. It also will cause a build up of pressure in the system, which the gasket won't like. Also there is a risk of the engine heat seizing itself.

Try bleeding the system as advised above, but if I read your original post properly, you said the viscous fan was not operating either, which won't help matters at all, particularly when ticking over or in slow stop/start traffic.

Post Mon Oct 03, 2005 3:59 pm

...i see.....scary stuff... will do tonight....

the viscous spins on idle and with the pully - but are they meant to get faster when needed? probably due to the head not getting the circulation....i see....

u saved me last time Beemerlad....fingers crossed...

Post Mon Oct 03, 2005 4:04 pm

viscous spins according to the speed of the engine fella and it pulls air through the radiator. So when you rev the car, the viscous picks up speed as it is driven by the engine. Once you are on the move, at say 40mph plus, the viscous stops working almost as the air flow going through the radiator cools the rad, so the viscous just slips itself on the inbuilt clutch. If the viscous kept running all the time when you were doing 80mph for example, you would get horrid MPG.

get the system bled how Brian suggested and take things from there fella. Please, i am no expert on such matters, it is just what I have learnt from 6 months on the zone from people like Brian et al

Post Mon Oct 03, 2005 4:17 pm

which hose do i unclip....by the radiator or engine???

Post Mon Oct 03, 2005 4:23 pm

ooops.... looking at the engine from the front of the car...left side or rigth side and which end????

Post Mon Oct 03, 2005 4:38 pm

the heater hose Brian is on about (as you stand at the front of the car looking back at it) is on the right hand side and goes from the engine through the bulkhead, over in the region of the brake servo

I am assuming your car is a 320/325 (m20 engine)?

Post Mon Oct 03, 2005 4:40 pm

HEATER HOSE at the bulkhead.

Post Mon Oct 03, 2005 4:56 pm

don't know if this pic will come out but I have drawn an arrow where I think I can see the top heater hoze going to the bulkhead (Brian -correct me if I am wrong) also arrow pointing to thermostat bleed nipple.

Post Mon Oct 03, 2005 5:25 pm

m40.....4cyl

i wish it was a m20....

Post Mon Oct 03, 2005 5:49 pm

in which case my photo of my engine bay ain't much use is it fella

See how you get on, if you get stuck I'm sure somebody can post up a pic of the M40 pointing to the necessary bits.

Post Mon Oct 03, 2005 6:42 pm

my m42 currently overheats unless i leave the heating on

is this the same problem??

good job its winter

im bleeding it this week but not to sure how

any advice to coinside with the above? deffo sounds liek u need a new fan tho mate!

Post Mon Oct 03, 2005 8:36 pm

318is - Dan isn't it?

If your car is running high even when driving at constant reasonable speed or when at high speed cruising I would be looking at the following

Why is it high when good air flow running through the rad? I would look at dropping the coolant and whipping out the rad and giving it a flush through with a hose pipe. Check the condition of the rad and carefully try and remove any beasties and other smeg that clogs up the fins, if you have access to an airline all the better, just be careful not to damage the rad really. Follow procedure for refilling coolant system, heater on max temp when filling and starting for first time, bleed screw open etc and bleed as necessary. Would look at thermostat too, poss worth changing, prob Ãƒ”šÃ‚£10 or so from GSF, Ãƒ”šÃ‚£25 at stealers. Check viscous is alright.

If that lot don't work then maybe you have head gasket probs on the horizon possibly.

Just my thoughts and what I would be checking

Post Mon Oct 03, 2005 9:10 pm

Brianmoooore, E30BeemerLad thanks very much...

the bleeding techinque worked.....the car doesnt overheat now and the thermostat was 25 for GSF ansd it is all good.....

Big thanks....i love this place...

Post Tue Oct 04, 2005 12:19 am

E30BeemerLad wrote:in which case my photo of my engine bay ain't much use is it fella

See how you get on, if you get stuck I'm sure somebody can post up a pic of the M40 pointing to the necessary bits.

Heater connections on the bulkhead are the same whether 4 p[ot or 6 pot.

Post Tue Oct 04, 2005 8:23 am

beemer lad mate, yes its dan

and at high speed its fine i think without the heating on, went out yesterday an it sat slap bang in the middle for sum reason and didnt move

its once its been there for 20 minutes it starts to get rathe warm

im not to sure mate, think i mite just garage this one altho i no youl hate me for giving up :lol;!