Engine Overheating :(

[Guest Jon4547]

Right as of up to today i have had no heating in my 1991 205 CJ, the heater matrix pipes had corroded and the owner before me had bypassed it.

 

today the new pipes arrived and i gladly replaced them and connected everything back up.

 

the heating works like a treat, burns your face off lol however..... no my engine is overheating, the water is boiling, a red light has appeared on my dash (guessing it's an engine management light, it's in the very bottom right corner) and the fan on my radiator aint turning on. plus if you open the bonnet, your face melts with the shear heat from the engine.

 

i am not a very mechanical person when it comes to cars and just want it in perfect working order

 

does anyone have any ideas on what could be causing this??

 

cheers, John

[M@tt 77]

1st job would be to bleed the system properly. Go round all the vent points and open them up one at a time till you get a constant trickle of fluid out of them. To help bleed i always find it useful to raise the revs slightly and give all the rubber hoses a good squeeze/massage to help joggle and trapped pockets of air along.

 

I'd also check your thermostat. Take it out and bung it in a pan of boiling water and check it opens, or for the sake of a bout £6 or so just get a new one and bung it in.

 

check your fan still works by bridging the 2 pins on the loose test plug which hangs down the passenger edge of the radiator. The fan should kick in when you bridge the 2 pins.

 

It may have been that the thermostat was sticking closed not allowing heat out to the rad and so the temp sensor switch in the rad wasn't kicking in as the water there wasn't hot enough and the hot water was just circulating in the engine.

 

HTH

Edited April 15, 2010 by M@tt

[Lan 24 1 Cars]

the engine used in the CJ is a TU engine this should be posted in the TU engines section, have you correctly bled the cooling system i.e. by hanging the expansion tank up onto the bonnet? the engine will only bleed correctly if this has been done as the expansion tank in normal position isn't the highest part of the cooling system.

 

as for the fan give it 12v and see if it works if it does the thermoswitch has gone

 

.... beaten too it

Edited April 15, 2010 by Lan

[M@tt 77]

good call by Lan regarding lifting the expansion tank up higher when bleeding the system

[jackherer 543]

This is in the wrong section assuming your CJ has the original TU 1.4 engine?

 

TU engine coolant systems are harder to bleed air from than XUs which virtually do it themselves.

 

If it was fine before you fitted the new matrix then it will just require a lot more bleeding before you get all the air locks out.

 

Edit: far too slow

Edited April 15, 2010 by jackherer

[miamichris 9]

Tu's are a bollocks to bleed, just changed the thermostat, fan switch, cleaned out the level sensor and flushed the system out on my Xs so a bit of a cooling system overhaul! That red light you mention is probably one of the low coolant or high temp. warning lights.

 

Hang the expansion bottle up high, off the bonnet worked for me.

 

Take the radiator cap off and make sure its filled up to the top then put the cap back on, run the engine with the expansion tank

cap off and bleed at the thermostat housing first and then the top heater hose until no more air bubbles come out.

 

The air will bubble up through the expansion tank, once the engine is warm I just put the cap back on and took the car for a drive, stopping once in a while to SLOWLY open the expansion cap which releases the air from the system.

 

Good luck!

[Guest Jon4547]

thanks for all of your advice guys i really appreciate it!!

 

i'm going round to my mates now to bleed the system and i'll get back to you all on the results once it's done

 

John

[Guest Jon4547]

right....

 

the system has now been completely bled and the water does not boil, the fan works when i bridge the connections however, the annoying red light on my dash still shows up and the fan does not turn on automatically and the radiator gets piping hot

 

the light on the dash looks like water with a sort of cap or something on top of it, i'll get a pic of it tomorrow, the car still runs fine, i just don't want to run it too much and end up having to buy a new engine lol

 

any suggestions??

 

cheers, John

[jackherer 543]

Sounds like the low coolant light. The sensor is probably clogged up and sticking. Its on the expansion tank on a GTI, it might be in the radiator on a TU engined car I'm not sure. I'll move this to the TU section...

[Guest Jon4547]

Sounds like the low coolant light. The sensor is probably clogged up and sticking. Its on the expansion tank on a GTI, it might be in the radiator on a TU engined car I'm not sure. I'll move this to the TU section...

 

thankyou, it is the low coolant light, just looked it up lol, i'll fill the radiator up and see what happens

 

sounds very stupid but where is the refil cap on the radiator?? i was working on it in the dark

 

cheers, John

[tdr_1976 41 1 Cars]

You have to fill it up in the header tank, if you open the radiator cap, your going to have more air in the system.

[Guest Jon4547]

right.. is the header tank the plastic bottle to the top right of the engine bay near the bulkhead? i've filled up the system from there already..

 

oh and, does it matter if i get the pipes the wrong way round on the heater matrix, i have the bleed screw on the bottom hose and as air rises i have a feeling i have these the wrong way round and air is getting trapped somewhere

 

cheers, John

[M@tt 77]

yep hose with the bleed screw needs to be on the top

[Guest Jon4547]

yep hose with the bleed screw needs to be on the top

 

i knew it i'll get right on it

[batespeed 0]

there should be a bleed screw on the top of the radiator, on the drivers side. i fill the rad first, then open the radiator screw till you get rid of the air (keep the rad filled) then take the rubber band off the expansion bottle, lift it up above the level of the engine, and open the schreader valve (like a tyre valve cap ) in the top hose till you get the air out, keep the engine running all the time you are doing this. job done !

[Guest Jon4547]

Bingo!! all fixed now guys, just needed more bleeding... a lot more bleeding lol

 

cheers to everyone who helped!! much appreciated!!

 

John

[miamichris 9]

Bingo!! all fixed now guys, just needed more bleeding... a lot more bleeding lol

 

cheers to everyone who helped!! much appreciated!!

 

John

 

Pain in the arse to bleed aren't they?