T25 over heating problems

[whichedge]

Okay - had all sorts of problems with the Scooby Van (Caravelle 1.9 petrol 1983) mainly exhaust related which I have been sorted out but now I have a problem with over heating.

Over the past week or so the engine has been running hotter and hotter, until the other night when the temperature shot through the roof (almost literally). In fact it over heated and blew a senser out of the top of the water topper tank! And worse than that it's blown a head gasket. There is no heat coming out of the heater and the breather valve at the back of the engine doesn't seem to be venting the air in the cooling system either.

My question and conundrum is this, I take it that the head gasket blew as a result of the engine boiling up, and is unlikely to be the cause of the engine over heating, the amount of water that is coming out is only a very slow drip when the engine is running cold, I know that as the engine temperature rises the water will come out quicker. And what is this senser that is on top of the water topper tanker. There is no power to it at all and the senser what ever it is, is bolloxed, it's all rusted and nastie. I'm guessing that this senser is the fan cut in valve, and that either the wiring or fuse has had it, as well as the senser itself, which will result in the fan not engaging and the water not cooling, result boiling engine and blown head gasket. Or is more likely to be the thermostat or water pump.

Am I right in this assumption or not? Or is there something else that I have missed or should check? I don't want to drop the engine, replace the head gasket for it to blow again because there was something that I didn't check! If you know what I mean.

Finally and this may sound like a divit type question but is there only the one place (well actually 2 places) that water goes, the water topper tank and expansion tank next to it in the engine bay, or do I need to top up the water in the rad at the front (some how)

Any help would be greatfully recieved and if any one has a Haynes manual for a Scooby Van (Caravelle 1.9 petrol 1983) that I can buy or borrow please please, "on banded knee begging" .

This afternoon I'll remove the outlet pipe from the water pump to check that the pump is working, I'm not sure how to check the thermostat is functioning correctly, some help here would be appreciated.

Thanks folks

[jokerdub]

Hello sir.
1st off welcome to the forum.
Im Brick Top from Volkstorque. Ive a Haynes Manual you can borrow and me if you need my help. I work down by George Elliot (Listers Toyota) so Im not far from where ever you maybe.
Let me know bub.
Dave the man with many names

[tonytech]

The sensor on the water tank is the low water sensor and will light the flashing LED on your dashboard.
Fan switch is on radiator.

You only fill the topup tank. but may need to bleed the rad by lifting the front end 400mm.

Does the rad get hot? if not could be a failed thermostat.

T

[jokerdub]

You`re better off bleeding them on the flat. The up in the air at the front trick is a bit of an old wifes tale.

[whichedge]

Hello sir.
1st off welcome to the forum.
Im Brick Top from Volkstorque. Ive a Haynes Manual you can borrow and me if you need my help. I work down by George Elliot (Listers Toyota) so Im not far from where ever you maybe.
Let me know bub.
Dave the man with many names

Thanks for the offer, I may well be taking you up on it, if things don't go to well, which in my experience is often the case. I'm the other side of Nuneaton, on the Weddington Road. But I'll give you a shout.

Cheers

[syncroand101]

To test the thermostat...

Remove it, place it in a pan of water, warm the water up over the stove, ideally with a thermometer in the water, watch carefully and note at which temperature the 'stat opens (I have 87degrees in my head for the later VW ones - but I'm not sure). If it don't open at, or around that temperature its broke.

...Thats how I have tested 'em before, I am sure someone will correct me if I am wrong.

[jokerdub]

Jake, thats exactly how I test them.

[jokerdub]

Whichwedge, you now know where to get me, let me know and I will pop over to you after work one of the evenings.
Dave

[Arvi]

hi mate i live in Birmingham moseley

you can borrow book or prob easier if you let me have a fax number or address and i will copy relevant section for you

[whichedge]

hi mate i live in Birmingham moseley

you can borrow book or prob easier if you let me have a fax number or address and i will copy relevant section for you

Cheers

I found a link to the Bentley manual in the archives on here, the files are to large to download at work so I'll download them tonight at home. If there no good them I'll take you up on that offer.

Thanks Chris

[futurecut]

You can tell if the water pumps working by running at fast idle and squezzing the pipes. You can feel the pulsing if it's going (or diff between off)or you could just undoo the rad bleed srew a bit and see if coolant pishes out.

Apparently the sensors in the expansion tank disintegrate often- mine cracked through the middle and led to a secret coolant loss only under high revs and load when i couldn't see it or trace it. OEM is beter apparently.

You might also want to check fan is working by running wire between each terminal socket in the plug you pull out of the radiator- though you shouldn't really be needing it at this time of year- it gets really hot before the fan kicks in in mine anyway. You can check the operation of this thermoswitch too with hot water and a multimeter.

Air bubbles are a pain- i had one when i got my van but the bleeding operation wasn't half as bad as i'd been reading.

best of..

[kevtherev]

wiki could help

my mate had trouble like this he bled and bled and bled the bleeder till he got his circulation back it's ok now