Club 80-90 Forums

Hello all. i have recently bought a 1987 1600 td camper which has a overheating problem, it seems to be that on a run it just runs too hot , the van has had a load of work done to it including new motor radiator and water pipes. Also replaced was the aux water pump. The switch for that wasnt replaced and looks to be old, When the motor is running the gauge goes up to about 3/4 and seems to stay around there. I have priced up a new switch for this which is over 20 quid from my local vw dealer who didnt even have one in stock. My thoughts are to wire up the radiator fan and the water pump to switches and switch them on when the motor gets hot. Anyone any thoughts about the risks in this? Im not sure how long they would need to be left on to cool the motor down im guessing 5 minutes or so every now and again would probably do the job im concerned that i dont burn the water pump out with excess use.
Any thought would be greatly appreciated.

Aux pump and cooling fan are different things with different switches.

Rad fan is switched from sensor on the rad, might even be a 2 stage switch but even the first stage rarely comes on on my TD, seems the way they are. From memory they are ment to come on around 90deg in the rad. The few times my rad fan has come on its in slow traffic when the coolent guage wasn't that high. On a hill when I'm working it hard the temp guage easilly climbs to above the LED but soon drops again as the grade drops off, I tend to lift off in simpathy when the guage is above the LED aswell. On light loads its easy to get it to sit at the bottem of the LED. Does yours do this? If it likes being high and the rad fan never deals with it maybe you have a coolent flow issue? How is the main waterpump and drivebelt? How is the thermostat? New thermostats can be just as likely to fail as old ones, sometimes more so depending on quality. Is coolent system corectly bled and air free (heater not going hot is a good sign of airlocks)?

Another possability is its not getting hot at all, could just be a lieing sender. Only real way is the change the sender, luckally I think the heaterplug temp sender is the same as the coolent guage sender so swaping the plugs over should give you a second opinion - if nothing changes it probubly is hot as two senders failing and giving the same errorus reading is unlikely. If the coolent is bubbleing away and the heater burns your feet though I wouldn't bother suspecting the guage. DOn't go on the rad fan as if the coolent flow is low the heat might not reach that.

Aux pump is triggered by sensor on the engine, something silly like 107deg C. Engines unlikely to get that hot when running it but thats possable after the engines been switched off when hot as the lack of coolent flow means local water temps get high - thats what the aux pump is ment to deal with, destrebute heat a bit better and avoid engine warping. Having the aux pump on when the engines running isn't much use as the normal pump keeps flow going anyway.

Whilst these engines do run a bit hot and need a bit of simpathy about constant thrashing (flooring them for the odd hill is fine but Vmax on the motorway it won't like) their cooling system should keep things mainly in the normal band for normal driving, if it doesn't somethings wrong - try and fix that rather than do something else to hide the simptoms, it won't fix the problem, might not even hide it much!

thanks for detailed reply some useful stuff in there, i have today driven the van again about 3 miles, it got pretty hot fairly quick. I had noticed a switch on the dashboard which actually was connected to the fan switch previously, it would appear that when the previuos owner had a new fan and switch he disconnected the switch and relied on the original system. Ive put the switch back in place and wired it so that on the first position the front rad fan comes on ,on second position both front fan and aux. pump are running, this isnt an ideal situation but im hoping that it may me allow me to at least get some use out of the van before i really have to look into it any further. My ultimate idea is to ditch the motor and fit a 1900 unit into it which appears to be fairly straightforward. It seems a shame as the motor fitted hasnt done much mileage but has had this issue for some time, my gut feeling is that its been run hot and possibly warped the head or damaged its internals somehow. I bought the van cheap knowing it had this problem so im not that suprised about it!

villacamper wrote:thanks for detailed reply some useful stuff in there, i have today driven the van again about 3 miles, it got pretty hot fairly quick. I had noticed a switch on the dashboard which actually was connected to the fan switch previously, it would appear that when the previuos owner had a new fan and switch he disconnected the switch and relied on the original system. Ive put the switch back in place and wired it so that on the first position the front rad fan comes on ,on second position both front fan and aux. pump are running, this isnt an ideal situation but im hoping that it may me allow me to at least get some use out of the van before i really have to look into it any further. My ultimate idea is to ditch the motor and fit a 1900 unit into it which appears to be fairly straightforward. It seems a shame as the motor fitted hasnt done much mileage but has had this issue for some time, my gut feeling is that its been run hot and possibly warped the head or damaged its internals somehow. I bought the van cheap knowing it had this problem so im not that suprised about it!

My van had coolent issues when I got it too. Used to push its coolent out the tank behind the numberplate and empty the one in the engine bay triggering the coolent light every 100 or so miles. I never let it get properly hot but aparently it would when not driven carefully - I put a new head on it and its been fine, but then someone had spent a fortune rebuilding the rest of the engine so I thought it was worth forking out for a head to finish the job. If its not spitting out coolent though the head is probubly fine, though it won't be if it keeps getting hot. I'd try changing the thermostat, its not a big job and cheep; never know it might be the cure.

my gut feeling is that its been run hot and possibly warped the head or damaged its internals somehow. I bought the van cheap knowing it had this problem so im not that suprised about it!

It's not unusual

It might have cracked the head, but not warped it else the head-gasket would go, sounds like it hasn't (yet)..

Replace or test the fan temp sender in n/s of radiator - fan only comes on for about 20-30 seconds as its that powerful on a diesel. Check that fan actually works and can be triggered by 90 degree and above watrer temps

They do need and do use their fans when idling or when driving hard, a lot of heat is produced in these TD diesels.

Check turbo wastegate is opening (boost gauge or calibrate it with cycle pump)

A big oil cooler (19 row) up front is a very good addition to these vehicles
(oil can be putting a lot of heat into the oil/water heat exchanger, its a two-way process)

Check there isn't an inadvertant by-pass hose connection in the plumbing e.g. been messed with/thermostat problem.

Is it economical or really juicy?