P38A Another P38 Overheating Problem
- Thread starter Renniks
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I'd certainly imagine it'd be complaining but it might just be very hard to turn. Mind you, it'd be a hell of a load to cause the engine to overheat. I've only ever seen the gauge move going uphill with my foot on the floor, usually towing a few tons.
brianp38dse
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I think thats the only time my temp went up, under load up hill, then changed viscose fan and ok ever since touch wood cross fingers find a four leaf clover
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Unless the engine is pumping air into the system? Or a duff sensor reading.
Could just be the temp gauge sensor?
Could just be the temp gauge sensor?
That was my point that even if the aircon pump was seized solid, it wouldn't be enough load to make it overheat. It's more likely that with the aircon switched on, you are adding heat from the cabin to the radiator area.
Also, if the aircon pump was seized it would be worse at higher revs not better.
There are only two possible scenarios that would cause what he's experiencing,
1. Lack of air flow through the radiator.
2. Lack of coolant flow through the radiator.
Both of these would improve with more revs.
Renniks
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I think the aircon was a red herring. I realised I have been driving about with the front grill, slam panel and upper cowling off which has probably helped airflow. I put the slam panel and upper cowling back on and even with the aircon off, it overheats in the same manner (although only needs to be revved to 1000rpm to bring it down).
I'm thinking it must be airflow related. The viscous fan is definitely engaged though, even from cold (don't really see the point in a clutch if it is engaged from cold, to be honest). I've attached a couple of pics from the rad set up to see if anybody can notice anything amiss. The grill looks after market so I'm wondering if that is restricting airflow, although it is still overheats, even with it off.
The expansion rank pic is with the car running; can't see any stream of coolant; although there is a pipe that goes to the bottom of the expansion tank so perhaps it fills from the bottom (if that makes sense).
I'm lost again...
Looking at those pics, there seems to be a lot of fins bent over on the aircon rad and it looks like there's been birds nesting in there!
If it were me, I'd get all the rads out, straighten all the fins with a blunt object (old butter knife works well) then backflush the coolant rad and try again.
Also check the underside of the bumper isn't obstructed, a lot of the airflow goes through there too.
Can't tell properly but it looks like the header tank might be a bit over full. If so, you won't see the return from the small pipe. Not sure if that will affect it but it won't help your diagnosis.
Obviously, if you take out the aircon rad, you're going to have to recharge the aircon. I'd also consider a new aircon rad whilst it's out if there's any sign of corrosion at the top corners. They are prone to leaking there. (from memory, they're about 130 quid from euro car parts)
The viscous fan feels locked when it's cold but after a very short spell at anything above idle it will be loose or you would hear it roaring like mad. Then as the engine heats up, it will start to lock up to increase airflow.
Hence, when it's hot, a bit of revs helps.
I'm pretty sure if you clear the path for the air your problem will go away.
If it were me, I'd get all the rads out, straighten all the fins with a blunt object (old butter knife works well) then backflush the coolant rad and try again.
Also check the underside of the bumper isn't obstructed, a lot of the airflow goes through there too.
Can't tell properly but it looks like the header tank might be a bit over full. If so, you won't see the return from the small pipe. Not sure if that will affect it but it won't help your diagnosis.
Obviously, if you take out the aircon rad, you're going to have to recharge the aircon. I'd also consider a new aircon rad whilst it's out if there's any sign of corrosion at the top corners. They are prone to leaking there. (from memory, they're about 130 quid from euro car parts)
The viscous fan feels locked when it's cold but after a very short spell at anything above idle it will be loose or you would hear it roaring like mad. Then as the engine heats up, it will start to lock up to increase airflow.
Hence, when it's hot, a bit of revs helps.
I'm pretty sure if you clear the path for the air your problem will go away.
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Airflow?
Blocked Intercooler/Oil rad in front of the upper section of the water rad where its possibly the hottest and needs the most airflow for cooling and it just isn't getting it?
Is the viscous fan is trying to pull air through a blanket of crap in front of the new radiator?
Its disease-el so not something I am familiar with. Sounds like you have a real conundrum there.
It can't be waterflow with a new pump and radiator (unless you are air-locked), so it has to be airflow.
Blocked Intercooler/Oil rad in front of the upper section of the water rad where its possibly the hottest and needs the most airflow for cooling and it just isn't getting it?
Is the viscous fan is trying to pull air through a blanket of crap in front of the new radiator?
Its disease-el so not something I am familiar with. Sounds like you have a real conundrum there.
It can't be waterflow with a new pump and radiator (unless you are air-locked), so it has to be airflow.
Renniks
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Yep, next job is to remove the aircon rad I think. The aircon has never worked and is not something I'm bothered about. Is there any need for me to have the aircon rad there or can I get away without it? I'm just thinking if it will help airflow, I will just dispense of it for now!
I'm guessing I need to strip it all down again to remove the aircon rad? Fan, cowling, radiator etc, or can I get away with just taking the slam panel off?
With regards viscous fan, if I put a few revs on from cold, it should disengage and then re-engage when it gets hot? Have I interpreted that correctly?
I'm guessing I need to strip it all down again to remove the aircon rad? Fan, cowling, radiator etc, or can I get away with just taking the slam panel off?
With regards viscous fan, if I put a few revs on from cold, it should disengage and then re-engage when it gets hot? Have I interpreted that correctly?
You should have at least one (possibly 2) plastic "wings" on the side (if its 2) that directs air in to the rad, if they are missing a lot of air will miss the rad and be directed away, instead of it being pushed and forced into the rad itself
Aircon rad can be removed by taking the slam panel off. You will also need a looong extension to get the two bottom bolts through the bumper.
Should be fine without the aircon rad in as the compressor clutch shouldn't engage.
If nothing else, you can try it and if it solves the overheating then you will know what the problem is.
On the viscous fan, it never completely disengages, insofar as it will always turn.
However, the amount of torque transferred from the engine to the actual fan will be almost nothing when cold, a bit more when normal and close to fully locked when it's getting hot.
Renniks
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Plastic wings? Come again what are they and where should they be!?!
brianp38dse
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The viscous fan will always turn round it never stops, it just turns slower then engine speed if it is cutting in as the temp rises you will hear the thing roar like a mad thing, makes the car sound like a tank.
your grill looks original btw
your grill looks original btw
myfirstl322
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Steady on Dopes, You'll have Alan roused again with that description!!
Last edited:
kds
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I wonder if something else going off here, I took the fan off mine several years ago now (datatek mod) and fitted a thermostatic switch set at 95c and engine would sit at just under mid point on gauge fans kick just over mid on gauge, now the thing is I have just changed the engine (started pressuring up so head gasket, number 4 injector leaking again, injector pump tired and needed new dmf and clutch) so got a good deal from local breaker I deal with for engine bought new dmf and clutch had to change over full engine wiring loom, water pump and stat even swop both sensors in the head with me so far ? So now the interesting bit, the temp gauge now sits about a third up the gauge and the fans still kick at 95c even with stat, pump and sensors from old engine, work that one out because I cant ! So is his engine over heating or is something else going on ? sorry a bit long winded.
myfirstl322
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kds
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I might be a little silly at times but I aint that bad !
