HELP!! overheating problems

[johnd]

Hi all need some help with my p38 4.0 1999, it has been overheating on and off for a month firstly it was the small gasket under the throttle body i replaced it then 2 days later the radiator bottom hose which dumped the coolant all over the road. But tonight after 4 days of use the temp went up in to the red but lost no water.
After i replaced the bottom hose i pressure tested the cooling system and there was no pressure loss.
does anyone have any ideas as to what this could be as i think its going to be a matter of time before i fry the engine.

Please help....

cheers
john

 

[bryhp]

maybe the thermostat?

 

[johnd]

Thanks for the reply, i forgot to mention that the thermostat was replaced when the engine was rebuilt about one and a half months ago. Also tonight when it over heated the radiator top hose was rock solid.

 

[gavbriggs]

is it gas?
was you running on gas. if so try running on pertrol only sometimes gas can raise the engine temp too high if burning too lean

also p38's are known for o/heating and porous block syndrome!

have you tried taking the small pipe off top of rad when filling to help get rid of air. also turn heating on full as this will circulate water through heater core

check rad for even heat distribution as it could be blocked/limited flow also is fan turning???

 

[johnd]

No its not gas, i had the heaters on but it made no difference.

 

[gavbriggs]

when engine was rebuilt what was the original problem?

the hose bieng sold is a symptom of air/gas in the system, no gas then it must be air!! when i refilled mine i it took ages to get the air out!!

 

[johnd]

The engine was rebuilt about 2 months ago the headgaskets had gone when i bought it but maybe there was an issue that caused the headgasket problem in the first place.
How can i get all the air out of the system?

 

[radron]

Hi take the cap off the water reservior and let the car run it should let the air bleed out. Let it settle over night and top up in the morning. It might be worth flushing the system out with a hose.

 

[johnd]

so i should just run the engine with the cap of to bleed the system, how long should i run it? And will it not just start bubbling out?

 

[gavbriggs]

it should bubble the air out but the water level will drop, keep a kettle full of water at the side of you and top up, try not to let the level drop too much, also put the heater on full too. watch the temp guage tho!

 

[johnd]

ok i had the car running for about an hour and there was loads of air bubbles coming out, i kept the water topped up and the temp gauge was just under half way. Then it decided to turn into a fountain the water came flying out of the tank about a foot high.
I cant see this being normal is it?
And also just before that the heaters went warm rather than hot.
does this mean anything to anyone?

Also there is a very small hole at the top of the expansion tank which i am told should let water in and show that the water pump is working but i cant see any water coming in is this information correct?

sorry for all the q's
any help will be gratefully recieved.

 

[Disco Moneypit]

Oh dear.

I really don't mean to sound alarmist, but these symptoms sound just like the problems that I had on the Chim. It ended up being a slipped bore liner.

You could have them top hatted, (do all 8, not just 1), if you haven't done too serious damage to the block. Failing that, your block is scrap.

TVR Power are currently doing brand new CosCast blocks for £1000 + VAT.

Good luck, but it sounds like your motor is fubared.

 

[Series71]

check the water pump and belt might be an idea ?

 

[gavbriggs]

it could have just been an airlock that got released and pused the water out, any news on this problem???

i know mine did it at one point, not a foot high though, then took more water in, temp is usually just over the halfway point on the guage and never goes any higher

 

[johnd]

thats what im hoping!
i have had enough of it so i have just ordered a complete hose kit, thermostat, water pump and radiator just for peace of mind as my missus will be driving it and she is 8 months pregnant and really dont need it to break down when shes driving it, that would be more than my lifes worth, lol
will let you know how it goes.
cheers for all the help.

 

[gavbriggs]

on one of the other threads i suggested rigging up some kind of bleed valve, maybe making a 't' piece to fit in one of the higher hoses on the car, seen as you have all the hoses you may be able to help the cause by rigging something up yourself. let us know how you get on!

 

[johnd]

Good thinking will get on the case as soon as it all arrives in the morning.

 

[redrenger89]

Sorry to hear of your problems

When I replaced my thermostat I checked it first with hot water while it sat in a mug.
Then fitted the new stat with the top hose disconneted from the block, filled the rad by bending this hose up and back. when full I replaced hose and ran the engine to force any air up to top, pulled hose off and topped up, ran engine again tightened the hose clip.
After a minuite or two squeeze the hose quickly with both hands to expel any air and top up tank if reuired.
Check small bore hose to tank to see if water is being pumped. you can see it if the tank cap is off.
Replace tank cap and run engine for a few minuites checking tank level.

This worked for me

Good Luck

 

[Hackett]

thats what im hoping!
i have had enough of it so i have just ordered a complete hose kit, thermostat, water pump and radiator just for peace of mind as my missus will be driving it and she is 8 months pregnant and really dont need it to break down when shes driving it, that would be more than my lifes worth, lol
will let you know how it goes.
cheers for all the help.

I think you are my parrallel world twin or something.....we both have exactly the same problems, the same car and our mrs's are both 8 months pregnant.....please post in my thread if you sort it out, ive replaced the stat, water pump, head gaskets and skimmed heads and its still doing it.

Good luck mate

 

[gavbriggs]

you dont think hakett and john have the same missus and she just likes range rovers do ya??? it's getting like jeremy kyle in here!!!!!