P38A Another P38 Overheating Problem

Hello All,

My first post and, typically, it is a request for advice! However, I am reasonably certain I will be spending quite a bit if time on this forum as it seems to have a wealth of information that I am pretty confident I will need, considering my new purchase!

Ok, so I have done what everybody says not to do and bought a cheap (sub £1k) 1996 P38 (you can stop sniggering now). It has 12 months MOT on it, without any advisories (has to be a bargain surely - or perhaps not!)

In honesty, I only wanted a vehicle to run up and down the single track lanes around where I live (althoughI doubt I will be doing this very quickly as it is the 2.5 diesel with an auto box) As such, I wasn't particularly bothered about cosmetic issues (and, unspursingly, my purchase does have a few). However, more worryingly, the P38 does have an overheating problem as well.

I am reasonably confident it is not a major issue and it seems to be more to do with airflow. The car runs really well when moving and the temperature needle stays bang in the middle. I drove it 195 miles home and it didn't miss a beat. However, as soon as you stop moving for a minute or two the needle starts to shoot up.

I have searched this forum and, from what I have seen, it seems to point to a viscous fan issue. I'm going to do the rolled newspaper test later today. However, I was wondering if anybody has any any suggestions as to any other 'diagnostic' tests I should do whilst I am at it?

I'd appreciate any suggestions anybody has as, although reasonably technically minded, I am a complete novice when it comes to P38's!

Thank you all, very much, in advance!

Check viscous fan for function your symptoms are classic of fan failure. Are you losing coolant?

wammers said:

Check viscous fan for function your symptoms are classic of fan failure. Are you losing coolant?

Click to expand...

Thanks Wammers. Yes, my research to date points towar the viscous fan.

In terms of the test, I'm assuming it should only 'engage' when the temperature goes above half way? Is that correct or should it be engaged all the time (I have seen conflicting points of view on this).

I can't see that I am losing coolant, no.

Renniks said:

Thanks Wammers. Yes, my research to date points towar the viscous fan.

In terms of the test, I'm assuming it should only 'engage' when the temperature goes above half way? Is that correct or should it be engaged all the time (I have seen conflicting points of view on this).

I can't see that I am losing coolant, no.

Click to expand...

No it will turn all the time but should tighten up when temp rises. It should then turn at around 80% of the water pump revs and be difficult to stop. Roll up a newspaper fold it in half. Grip the folded end. Then standing in front of the car with engine running and up to temp, apply to fan at right hand side looking back. If fan stops it is duff. If paper shreds it is fine.

It also may have had the cheapest after market rad fitted in the past. These are missing an internal baffle and so the coolant doesn't flow through the rad, but just along the top of it. This of course doesn't provide much cooling for the coolant.

I have a V8 so I'm not sure if you can identify one from just looking at it, but @wammers or @Grrrrrr might...

wammers said:

No it will turn all the time but should tighten up when temp rises. It should then turn at around 80% of the water pump revs and be difficult to stop. Roll up a newspaper fold it in half. Grip the folded end. Then standing in front of the car with engine running and up to temp, apply to fan at right hand side looking back. If fan stops it is duff. If paper shreds it is fine.

Click to expand...

Perfect, that's what I assumed to be the case; some movement when cold but not 'engaged'.

Well, I'll give it a go. I highly suspect that it is probably the issue. If it is, I'll be ordering a fan clutch spanner and new fan from eBay, I guess.

Thanks for your clarification!!

Renniks said:

Perfect, that's what I assumed to be the case; some movement when cold but not 'engaged'.

Well, I'll give it a go. I highly suspect that it is probably the issue. If it is, I'll be ordering a fan clutch spanner and new fan from eBay, I guess.

Thanks for your clarification!!

Click to expand...

All you need is the correct size spanner and an hammer to shock it. Fan is L/H thread and unfastens in it's direction of rotation. Clockwise looking from front of car. Cowling comes off and goes back on with fan. It's a bit of a fiddle. One tip, get a good quality fan, not a cheap and cheerful version.

Thanks MrGorsky,

I'll take some pics and post them up later. I'm very much hoping it is just the fan!

wammers said:

All you need is the correct size spanner and an hammer to shock it. Fan is L/H thread and unfastens in it's direction of rotation. Clockwise looking from front of car. Cowling comes off and goes back on with fan. It's a bit of a fiddle. One tip, get a good quality fan, not a cheap and cheerful version.

Click to expand...

Thanks Wammers. I've watched a couple of videos so will definitely be having a go at it. It the 32mm spanner I need, isn't it?

With regards the new fan, I will obviously be wanting to keep costs as low as possible, given what I will be using it for. However, I also don't want to spend money on something that is not fit for purpose. Is there a particular type of fan that people usually go for?

Ok, so this may not be as straightforward as I thought...

Fan is engaged, even from cold start. When sitting on the drive from cold, it takes a while to get up to temperature and the needle seems to remain in the middle with no issues. Take it on a drive and it is fine, until you stop when it gets hot very quickly.

The aux fans don't seem to come on. However, having had a good look around the engine bay, it seems there is a lot of water marks. I have also noticed what appears to be an oil leak from the head gasket (disappointed I didn't notice it when I picked the car up). There is no mayonnaise on the oil filler cap though.

I've attached a few pics but any pointers as to any more tests I can do to see if it is the head gasket or something else, would be great!

Wouldn't say that's the head gasket more likely to be rocker cover gasket. Thermostat stuck in closed position perhaps or air lock in cooling system. Try removing small pipe at the top of the rad.

stemac33 said:

Wouldn't say that's the head gasket more likely to be rocker cover gasket. Thermostat stuck in closed position perhaps or air lock in cooling system. Try removing small pipe at the top of the rad.

Click to expand...

That's a good point actually; it is rocker cover and not cylinder head.


It is certainly a bit of a strange one. The aux fans not coming on won't be helping but I can't imagine it would have such a huge impact.

I guess it's trouble shooting time! Will removing the small pipe at the top of the rad help bleed the system? I used to run the car with the expansion bottle top off.

the little fans being used will depend on the year it was made, other than being use for the aircon, the later buses (if im right wammers)? Used the little fans to help cool the engine also??

nice colour ..

do you have? Not a smutty question.. A wet rug!!

rephrase.. Drivers side carpet underlay??

I do actually really like the colour, although that is probably the last of my considerations when it came to buying one!

I've had a read of the Rave manual and think I am going to just bleed the whole system and refill it, hopefully that will help.

I was also thinking about changing the thermostat. Is this a pretty simple job?

Mark Piercy said:

do you have? Not a smutty question.. A wet rug!!

rephrase.. Drivers side carpet underlay??

Click to expand...

That is one thing I did actually check. No signs of 'wetness' on the drivers side transmission tunnel, if that's where you mean. The heaters seem to be a bit hit and miss which I understand can be down to the blend motor. However, I suppose it could also be a symptom of an airlock?

Could be water pump on its way out.

The fan will be locked when cold, free up as she warms (you'll hear the engine quieten) and then lock as she gets hot. Don't think air con fans do much on the 96 oil burner.

Only way to check baffle is put your hand on different parts of the rad. If suspect try rolling a marble across the pipes when out and empty.

Viscous. One off Island 4x4 should be fine.

Electric fans on my 96 oilburner only do the air con. Should the fan not be free when cold and lock up when it's hotter engine needing more cooling fan spins faster so to speak?