Can anyone help me I have 96/7 p38 and have started to experience engine overheating. There is no gasket probs I can assure you. The problem seems to only occur when I drive over 20-30 miles (never around town even when engine is at opps temp). The problem seems to be enhanced if I turn the AC on!!! The engine can be cooled down by turning the AC off and the heater up to HI and cranking up the heater blowers. I am not sure I can hear the Rad Fans coming on, as I am sure I used to how can I test them without running the engine. Do they operate by thermostat!!!! I would be very grateful if anyone can help
j the range
New Member
hang on you dont say wether it petrol or desel. if its petrol you cant run it without the stat. get a news paper roll it up, start the engine and see if you can stop the fan. if its easy to stop the fan is foooked.. the hotter it gets the harder it should be to stop the fan..
rewmer
Well-Known Member
Oh Jesus..........
How about some more info and we may be able to offer some sensible advice. Petrol? Diesel? Powerbox? any remedial work done?
Sounds like you have a problem with aircon fans get them checked out.
Sorry, not enough info - so here goes - 4.6hse petrol, engine replaced about 5k's ago, engine runs fine around town at normal temp. if I turn the AC on, normally only on longer trips, the engine overheats at about 20 – 30 miles. I have since checked the large fans (I take to be the AC fans) at the front of the Rad compartment as I no longer seem to hear them coming on as they used to do (have taken the grill off and checked – they do not come on, on their own – at any temp even very high temp). They were full of debris so they obviously haven’t been working, I have cleaned them and can run them by bypassing the power to them (cleaned all contacts) and by shorting the Relay, can I check the Relay by using a AMP/Multimeter? If so how – I am no Electrician. Thanks for you help so far.
robp38
Well-Known Member
first thing is to get a sniff test done on the coolant. check all pipes condition rad cap pump thermostat and radiator.. is the top hose over pressurinsing ? the way it seems to me is that the aircon fans at the front do have an effect on the engine cooling but are primarily there to cool the aircon radiator.. are you constantly loosing coolant.. eg topping up daily/weekly etc.. you cannot run a petrol p38 without the stat... worth getting a new one as they can get buggered up by the engine overheating... cheap ish.. try island 4x4..
how are you pssitive that the head gaskets are ok ??? if these cars overheat the heads can warp !!!
good luck
how are you pssitive that the head gaskets are ok ??? if these cars overheat the heads can warp !!!
good luck
Cheers, i am sure the Head is fine, there is no water in the oil for example, as for the over-pressurisation of the top pipe - it is hard when hot but i would have thought that was normal in a pressurised system.
Thermostat seems to be working from what I can gather - top pipe cold when started, gradually getting warmer then hot when Thermostat kicks in!! - I am most concerned re the AC cooling fans I am unable to get them to kick in even when I short the AC cooling switch in the dash, I think I'll have another go at the relays - thank again
Thermostat seems to be working from what I can gather - top pipe cold when started, gradually getting warmer then hot when Thermostat kicks in!! - I am most concerned re the AC cooling fans I am unable to get them to kick in even when I short the AC cooling switch in the dash, I think I'll have another go at the relays - thank again
First of all those fans are not for cooling the engine. They will come on at low speed to assist engine cooling IF aircon is on. If your aircon condensor is full of crap it will be blanking airflow to radiator. If the aircon fans are not working at all (with aircon on) and the condensor is blocked, that is why your overheating. There is sadly only a very fine line between running at correct temp and overheat on these engines. Everything must be just so or you get problems.
Yes that is the condensor. They tend to get full of debris and block airflow through rad. If vehicle does not overheat around town but does so at 50 60 70 mph then i would think you have an airflow problem. At those speeds there should be enough airflow through rad to cool it without any fans at all.
cossiedave
New Member
it will be your radiator mate, my old p38 did the same and i tried all sorts, in the end i bought a lazer heat tester and it told me the rad wasnt heating up all over so put a new one in and you could sit at 90 on motor way and it was fine, rad was 130 of ebay but make sure you dont get one for the thor as the top pipe is on the wrong side
kernowdragon
Well-Known Member
The Aussies, used to these high weather temps, recommend replacing P38 rads every 90-100k, as they clog with crap!
j the range
New Member
have a look at budget radiators, for a rad. i got mine there, for a thur engined rr..
kernowdragon
Well-Known Member
In theory the AC fans should only kick in if the rest of the system can't reach the right temp without them; therefore unless your AC is showing a fault i.e. book symbol when set on max chill, they are probably operating correctly, just not needed.
