Overheating problem, what could be a reason?

[patkop79]

Dear All,
Could give me any clue what could be a reason of overheating on my R75, please?
(1.8 petrol)

I'm starting engine in the morning and after 5-10 minutes I'm reaching around 90 deg C but few minutes later I'm getting max/red!!

Coolant tank is fine, coolant level correct, radiator work fine and is cold as glass.
I've fitted new thermostat today, but no change, still overheated....

Water pump changed 1 year ago and HGF done beginning of this year.

What you think guys?? :confused:



I'm really worried now :getmecoat:

regards
Patrick

[7.5]

Could there be an airlock?
Is the fan working on all speeds?

[patkop79]

Could there be an airlock?
Is the fan working on all speeds?

Yes you're right, could be airlock - just read about it.

Do you know how to relief air now, please?


Fan works fine on all speeds.



Kind regards
Patrick

[Jules]

Get an MOT station to probe your header tank for CO/HC readings with their exhaust analizer.

Could be HGF again if job not done correctly. (hope not though of course):o

[chrissyboy]

is fan running on when you have turned the car off ,you say rad is cold ,it shouldnt be ,check all pipes are hot ,,i would say you have a blocked rad , or lots of ir in the system.try to bleed the system until you have no air in there and the coolant is running out in a steady flow .

[T-Cut]

It might be a thermostat issue. How long since the HGF work has this rapid heating been apparent?

TC

[patkop79]

is fan running on when you have turned the car off ,you say rad is cold ,it shouldnt be ,check all pipes are hot ,,i would say you have a blocked rad , or lots of ir in the system.try to bleed the system until you have no air in there and the coolant is running out in a steady flow .

yes, fun running ok when car off

pipes are hot but rad is cold

I'm not sure how to bleed the system right now :shrug:



thank you :bowdown:

[patkop79]

It might be a thermostat issue. How long since the HGF work has this rapid heating been apparent?

TC

HG been done beginning of this year and new thermostat fitted

two weeks ago, on normal ride (40-45) temp reach max, left engine to cool down and back to home at normal temp, put to garage, next day to check it but no problems at all, so I was driving for two weeks without any problem, I was checking coolant every few days and was ok and then two days a go on the motorway (60 mph) temp reach max, called RAC to take me home, been advised to fit new thermostat, done it yesterday but temp after 10-15 min reaching max

I need bleed air from system - that's for sure but not sure how

then I can look for more causes



thank you

[SD1too]

yes, fun running ok when car off
Ideally, this shouldn't happen and indicates that the engine is running too hot.
pipes are hot but rad is cold
Have you got a PRT (Pressure Relief Thermostat)? It's a plastic moulding behind the radiator with three coolant hoses attached.
If you have, then you need to remove the standard thermostat at the engine block.
If you haven't, then the indications are that your new thermostat is not opening.
I'm not sure how to bleed the system right now
If you search using my user name you'll see that I posted the official MGR instructions for the 1.8 engine only a few days ago. Follow them precisely. Don't cut corners.

Simon

[patkop79]

Have you got a PRT (Pressure Relief Thermostat)? It's a plastic moulding behind the radiator with three coolant hoses attached.
If you have, then you need to remove the standard thermostat at the engine block.


[/QUOTE=SD1too;1390348]
If you search using my user name you'll see that I posted the official MGR instructions for the 1.8 engine only a few days ago. Follow them precisely. Don't cut corners.

Simon

Yes I have PRT and this was fitted new now. But had no idea that thermostat on the back of block must be removed. Should I remove to check the problem and buy new one or remove completely and run car without it? :o

I managed to find small screw to get air out from the system but it not helped
Temp is still reaching max. So must be something else. :(

OK, now I'll try remove thermostat from the block.

thanks for help :)

[chrissyboy]

yes, fun running ok when car off

pipes are hot but rad is cold

I'm not sure how to bleed the system right now :shrug:



thank you :bowdown:

fan shouldnt run when engne is turned off ,it should stop.if it is running on after the engine has been turned off then the head is getting too hot .sounds like the rad is blocked so no circulation to the system. make sure you only have the stat in the prt ,the one on back of engine is a dummy one .the rad should be hot along with all the hoses,could also be an air in the sstem .it needs to be bled in order to rule out air lock.

[SD1too]

OK, now I'll try remove thermostat from the block.
Yes Patrick, come back to us when you've done that. Don't forget that you'll need to bleed the system again. Don't rush this; follow the MGR guide which I posted recently.

Simon

[patkop79]

Yes Patrick, come back to us when you've done that. Don't forget that you'll need to bleed the system again. Don't rush this; follow the MGR guide which I posted recently.

Simon

well, I have screwed out 3 bolts (2 on plastic part and 1 from block) the pipe is lose now - water/cooling is running out now, but - I can move pipe up and down but no chance to pull out :shrug:

Should I pull harder or maybe I missed something? :o

ta
p

[SD1too]

Patrick,

I don't have any practical experience of the 1.8 engine so all I can offer is MGR's procedure:


Drain cooling system
Remove air cleaner
Disconnect heater hose from thermostat housing
Remove 2 bolts securing coolant rail to block.
Release coolant rail from thermostat housing.
Remove bolt securing thermostat housing to block.
Remove thermostat housing from coolant pump.
Remove & discard two 'O' rings from thermostat housing outlets.
Remove 3 bolts securing cover to thermostat housing.
Remove thermostat & rubber seal from housing.


It's best to drain the cooling system before you start work, then you don't get coolant spraying and dripping into places where it can cause problems later.

Simon

[patkop79]

Patrick,

I don't have any practical experience of the 1.8 engine so all I can offer is MGR's procedure:

[LIST=1]
Drain cooling syst......................


Simon



THANKS a LOT!!!

:bowdown:

[patkop79]

Thermostat removed. Now I need to put back everything together and fill coolant properly.

Thanks

[SD1too]

Thermostat removed.
It's good news, in a manner of speaking, that you've found one fitted! :)

Simon

[chipsceola]

And if you found an incorrect thermostat fitted when HG replaced, beware of the garage that did that work, profile says a 2004 model, which would have a PRT factory fitted, so one at the back of then engine would have been a blank.

Cannot believe that an MG/Rover garage or an MGR mobile mechanic would have fallen for that.