1989 - 2.1 petrol panel van - Overheating without heating!

[Moss-Turpin-T25]

Hi all, thanks in advance for your help.

I have just purchased my first T25, a 1989 2.1 petrol panel van named Moss Turpin (don't ask) ready to convert (don't worry I won't be cutting any windows out). I have been driving the van with no issues aside from the fact that if i turn the heating off the temperature gauge begins to flash hot within 20 minutes of normal driving. However if i turn the heating on again it will drop straight away. Although the light suggests overheating I haven't noticed too much difference or any steam when this occurs. Could it be faulty? The previous owner told me he never turned the heating off to aide the cooling... I however can't handle sweating forever! He also mentioned that he removed the thermostat last year to help the cooling... this doesn't seem like best practise to me (I am a relative novice though).

Is it recommended that I fit a replacement thermostat? If that isn't the issue what else is suggested? Is there any way of troubleshooting the issue? a friend of mine who has owned a T25 in the past said that it could even mean that the head gasket may be on it's way out? The water level does drop slightly in the tank behind the license plate after a day of driving (It has also been very warm weather here in the UK though!)

I really appreciate any help and can give any more information that is needed!

cheers

Ollie

[patrickpawsey]

Basics first, yes there ought to be a thermostat. Removing it may mask symptoms but the reason for it being removed is what you need to find out, of possible, from the previous owner.
Running the heater can help if the cooling system is not working effectively, but that again indicates other problems and ought be diagnosed and dealt with rather boiling the driver!

Also congratulations and welcome, this is a great place to find advice.

The sensors can be faulty and can be tested, but the fact that the level in the system is dropping (possibly, the tank behind the license plate is the expansion tank, so it should fill up when the engibr is hot then get lower again when it cools) suggests that the system is struggling to cope with the temperature generated.

What I'd recommend doing is going through the wiki pages on cooling

http://wiki.club8090.co.uk/index.php/Ma ... ing_System" onclick="window.open(this.href);return false;

And definitely get a thermostat.

The systems can be hard to bleed properly, so it might be that an air bubble is trapped which is causing the system to run incorrectly, and all this thermostat removal and heater running is to try to work round that, but these engines are very sensitive to overheating, so it's definitely worth getting to the bottom of it asap to save the head gasket etc, if they are still intact.

Good luck and post a photo of the while engine bay if you can!

E D I T: also, buy all parts from Brickwerks, if in any doubt.

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[Moss-Turpin-T25]

Thanks for the reply Patrick.

I will speak with the previous owner and see the reasons for removing the stat and get that info back on here along with some photos of the engine bay.

i'm a little bit lost with what my next steps should be aside form taking it to a local specialist to have a look over and see if they can determine the issue. It seems through reading as though there could be multiple causes and I may need to try a fair few before the correct one is found!

Will revert back soonest.

cheers again.

[ajsimmo]

Poor flow. Either blocked rad (most likely), or a restriction elsewhere. Perhaps the metal inserts in the front to rear plastic pipes are corroded and restricting flow? Twisted/pinched main hose?

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[Moss-Turpin-T25]

Thanks for getting back.

If the rad is blocked will bleeding be sufficient do you think? Will check all pipes and hoses over the weekend to see if it's that also.

Thanks!

[nevill3]

I thought that with the thermostat removed the radiator fan will not turn on automatically. Have you checked either if the radiator fan is on constantly or starts when the engine begins to get hot as it should. Maybe there was a problem with the radiator fan which has been "fixed/bodged by eliminating it.

[Moss-Turpin-T25]

Hi Nevill3,

I have noticed this evening that the radiator fan only seemed to turn on once the engine was turned off. I drove around for half an hour to see what I noticed. I couldn't hear the fan switch on until I pulled over and switched off. Could this be the same thing?

Thanks!

[nevill3]

I may have been mistaken with my earlier comment. The thermostat on the engine regulates when and by how much hot water from the engine is allowed to flow to the radiator. Without a thermostat I presume the water is flowing through the radiator from initial start up ( this is not ideal) If the water is not flowing through the radiator due to the removal of the thermostat or blockage/air lock the only way to cool the engine would be to use the heater matrix (small radiator) as you have been doing.

This link has a very detailed description of our vans cooling systems ( I think it may be USA based though and there may be small differences)
https://www.gowesty.com/tech-article-details.php?id=74

The thermostat/switch on the radiator controls when the fan comes on and at which speed and so the fan can continue running with the engine off if the coolant is still above about 85C

At least you know that the fan works if you heard it.

[Moss-Turpin-T25]

Thanks for the link... all a lot clearer now. I shall replace the thermostat that was taken out and hope for the best. Must I then bleed the radiator?

As promised earlier here is a link to the photos of the engine bay and radiator - If you just copy and paste into the URL it should work. The images were too large to attach.


https://we.tl/t-auRLJh9OgZ" onclick="window.open(this.href);return false;


Thanks all for the help to date. Does anyone have a recommendation for a T25 specialist near North London

thanks!

[nevill3]

[T25Convert]

Looks to me like you have a large coolant hose wrapped in gaffer tape in the engine bay, so I'd start by having a look at whats underneath that - might just be a crude attempt to stop it rubbing on the clutch slave cylinder, but worth checking.

I agree with @ajsimmo - Sounds to me most like you have a blocked radiator, with the heater on you are supplementing the cooling capacity of the system (but not you!).

If it were me I'd flush the cooling system, new thermostat, change the radiator and bleed the whole system properly.

Looks like the hose between the two coolant tanks is an old cloth wrapped item, might be where your small water leak is occurring.

This is pretty basic - you could do all this using two spanners /sockets (10mm and 13mm) and a pair of decent pliers which you may well find is cheaper (and potentially better) than your local 'specialist' depending on exactly who they are....

[Moss-Turpin-T25]

Thanks for the thorough reply!

I'll begin by checking all the hoses as suggested and get the parts ordered.

Earlier it was said I should get the thermostat from Brickwerks... should I get the radiator from there also? It's not the cheapest! around £160 for the wider rad.

I'm going to attempt the work myself as suggested... necessary to learn a bit more than i currently know for when i'm on the road!

Thanks again all!

[T25Convert]

Brickwerks have a reputation as providing best quality parts. They may not be the cheapest, but they will fit.

If you fancy looking at alternatives AutoDoc have one of the widest ranges - https://www.autodoc.co.uk/car-parts/oem/025121253a" onclick="window.open(this.href);return false; beware shipping times on these though. You'll note that the same Hella rad is £185, making BW look good value.

I took a punt on a cheaper one from Autodoc - the NRF is a brazed radiator like the Hella, rather than the cheaper mechanically crimped type. It works.

To be fair, any will probably be better than the one you have on there now.

Just avoid ordering from Just Kampers at all costs as in my experience they are dire (others may disagree!)

[Moss-Turpin-T25]

Maybe committing to the Brickwerks one is best then in the long run!

Would it be worth testing the current radiator to ensure that's the issue before replacing completely or do all signs lead to that almost certainly being the problem?

Cheers!

[T25Convert]

Take off the lower grill as well and have a look at how the rad looks externally - I've seen a few where the bottom is effectively rotten.

You could pop it off and try flushing it, but results may be inconclusive.

Overheating issues can be a bit trial and error to solve, so it might not be the rad, but I'd suggest that replacing the old one will be money well spent in the long run anyway.

In your last photo it looks like you are also missing your 'card' baffles that direct airflow into the radiator which won't be helping matters - https://www.brickwerks.co.uk/brickwerks ... le-set-t3/