problems with cooling system

[feardana]

Hi, I'm a newbie in more ways than one but i'm keen to learn and i'll try not to be too thick/annoying in the process

we bought our bus a couple of months ago, 1985 2.0L diesel - it says it's a caravelle on an old engineers report we inherited but i'm not sure about that, (it also says leisuredrive/crusader on the hightop)

we took it to brittany for 10 days during the second half of july - anyways, everything went fine enough until towards the end of the trip when it woke us up at 2 in the morning because the radiator fan suddenly sparked into life making a racket on a very quite and otherwise family friendly campsite - the thing is the van had been sitting there with the engine off for several hours and i can only assume the engine was stone cold at that stage - the only thing i could think of outside of going thru all the fuses was to disconnect the battery which i did - when i reconnected the next day the fan started up again and it seems will run perpetually regardless of the temp of the engine so there was alot of messing around with the relevant fuse until we got it home.

However, on the way home, and even though the rad fan was running constantly the temp gauge started going off the chart and the red light started flashing every few miles so i'd stop, switch off the engine and the gauge would drop back to zero and when the engine started again the gauge gave no indication that the engine was anywhere close to hot and the air coming in from the vents was lukewarm at best and i know how hot that air can get when the engine's been running for a while so my own suspicions are that the heat sensor has gone south which could possibly explain the rad fan running the way it is but i didn't risk running it as long as the gauge was telling me it was overheating so hopefully there's no damage done.

Ok, finally, i brought coolant with me for the trip, (the pink stuff), and i had read in several places online that there are 2 coolant containers in the engine, one close to the number plate and another (with the dalek cap as i've seen it described somewhere) closer to the block - i can find a tank with the dalek cap but there is no tubing connected to this cap to facilitate flow and i can't find a second tank - am i missing something?

Also, even though we had dropped it in for a full service and thorough check up with a mechanic that we trust before we went and he had recommended the pink vw coolant the only coolant that i can see in the system seems to be the old bluish antifreeze and it looks cloudy and not in great shape - also, the level in the tank was above the minimum mark so i was reluctant to start adding anything until i straightened out a few things in my head first though eventually i did top up this tank and ran the engine for a while to see if the fan would stop running - it didn't and i haven't taken it out for a spin since i got it home -

does anyone have any suggestions as to what might be going on? many thanks for taking the time, regards

[Nicola&Tony]

(1) we bought our bus a couple of months ago, 1985 2.0L diesel . . .

(2). . . we took it to brittany for 10 days during the second half of july - anyways, everything went fine enough until towards the end of the trip when it woke us up at 2 in the morning because the radiator fan suddenly sparked into life . . . the thing is the van had been sitting there with the engine off for several hours and i can only assume the engine was stone cold at that stage . . .

. . . disconnect the battery which i did - when i reconnected the next day the fan started up again and it seems will run perpetually regardless of the temp of the engine . . .

(3) . . . on the way home, and even though the rad fan was running constantly the temp gauge started going off the chart and the red light started flashing every few miles so i'd stop, switch off the engine and the gauge would drop back to zero and when the engine started again the gauge gave no indication that the engine was anywhere close to hot and the air coming in from the vents was lukewarm at best . . .

(4) . . . i had read in several places online that there are 2 coolant containers in the engine, one refill and one expansion tank with the dalek cap as i've seen it described somewhere - i can find a tank with the dalek cap but there is no tubing connected to this cap to facilitate an overflow and i can't find a second tank - am i missing something?

(5) . . . full service and thorough check up with a mechanic that we trust before we went and he had recommended the pink vw coolant the only coolant that i can see in the system seems to be the old bluish antifreeze and it looks cloudy and not in great shape . . .

(6) . . . also, the level in the tank was above the minimum mark so i was reluctant to start adding anything until i straightened out a few things in my head first though eventually i did top up this tank and ran the engine for a while to see if the fan would stop running - it didn't . . .

Hello and welcome Oh flippy heck, that's a very long post with no breaks in it and a few different problems in there, so I've tried to break it up a bit to make it easier to reply to.

[Nicola&Tony]

Ok, with regard to no.1, I don't know much about diesel engines but there are a few different diesel engines so you need to find out what you've got in there. Whereabouts in the country / world are you? There may be other folk on here who are local to you and can point you in the right direction. Or take a photo of your engine bay and post it in this thread.

For no.2, sounds like your fan problem could be an electrical problem rather than an over-heating problem. The radiator has a switch on it somewhere which turns the fan on and off when needed. Sounds like this might need replacing. Here's an example (i.e. I don't know if this is the right part for your van):
http://www.brickwerks.co.uk/shop?page=s ... ory_id=110" onclick="window.open(this.href);return false;

For 3, 4 and 6, I don't know how many water tanks should be in your engine bay but again you may need to provide more info about your engine so that some of the diesel folk on here can help you. As you say, many vans have two water tanks, the header tank with the blue dalek cap and the top-up tank (or overflow tank). With that set-up the header tank should be full right to the brim (and the cooling system must be bled properly) and if it isn't, that can cause the problem with the temp guage that you've been experiencing. But it sounds like you've got an engine with a different cooling system on it.

For number 6, adding more water (and anti-freeze) won't stop your fan coming on. However it might fix the problem with your temp guage (but you don't mention if it did / didn't), as long as any air in your cooling system has been removed by bleeding it properly.

For number 5, don't add pink anti-freeze to the blue stuff. Just add plain water for now until the problems with the fan and temp guage are sorted (because potentially you might have to drain the whole system anyway to fix these problems). If you fix those problems without having to drain all the water out of the system, before winter you'd be well advised to drain the system anyway and replace it with a 50:50 mix of water and fresh anti-freeze (blue or purple), because you haven't had the van for long so you don't know when it was last changed:
http://www.brickwerks.co.uk/shop?page=s ... ory_id=110" onclick="window.open(this.href);return false;

Hopefully someone will be along soon to provide some diesel-specific info.

Tony

[feardana]

many thanks for that reply tony - in answer to your questions, i'm based in shannon co. clare, ireland

as for whether the engine has overheated since, i haven't actually driven it since i got it home as i wanted to get more insight into what's been going on.

i posted a few pics of the engine (7457), the coolant tank (7459) and another picture (7461) showing oil which has been on the engine recently - i've only noticed this very recently and the oil level is normal (somewhere between max and min), so i don't think it's overfilled and that's a bit of a concern also

The main points are that it's a 1985 T25, 2L diesel

that the cooling van is on all the time even when the engine is cold

that when i drive it the temp gauge indicates a moderate engine temp until suddenly it'll shoot up to max and the red light starts flashing but when i stop the engine the gauge goes back to min and there's no indication from the gauge or the air coming in from the fan that the engine is particularly hot - also, i did notice that this tended to happen alot more on an incline, particularly a very moderate but long lasting incline but when driving in ireland this describes 50% of our roads

many thanks

[andyb]

Looks like a 1.9D engine been fitted - not a particularly careful fit. There should be an expansion tank fitted for water which seems to be missing. The oil dip stick looks a bit messy - leaking? - I wouldnt trust the markings on the dipstick either as this engine now sits at a different angle that it did originally and there will be a different sump.
The cooling fan I would hazard a guess has nothing to do with engine - its up front of van you will need to look - at radiator thermo switch and at fan relay and other wiring.
The temp gauge problem - there are two temperature sensors on engine - one for glow plugs and normally the one at the back of the block for the guage - you will probably have to establish their functionality as a first step.
Looks to me like you still have the double spring set up on the throttle lever - interesting - does your engine hatch lid fit correctly? just out of of curiosity.

[feardana]

Hi Andy and many thanks for that - just a few questions

are you fairly confident that it's a 1.9D?
why do you think it's not well fitted?
were all original vw buses fitted with petrol engines?
and why should there be a second water container in the cooling system? - i don't really understand the idea of the 2 tanks anyway

as for the oil, yeah there does seem to be a leak unless as you say the gauge is unreliable and i've inadvertently overfilled it

the cooling system was actually overhauled shortly before we bought it and the hoses going from the engine to the rad are new

as for the engine lid, yes it fits fine and locks ok

does anyone have any suggestions as to the best way to proceed from here to start eliminating possible causes and is there a way to tell if the engine is overheating regardless of what the gauge is saying?

many thanks

[Nicola&Tony]

. . . and why should there be a second water container in the cooling system? - i don't really understand the idea of the 2 tanks anyway

Have you had a look in the wiki (link to it is at the top left corner of this page) there's a section there about the cooling system, including a section about how the header tank and top-up tank work in combination with each other:
https://club8090.co.uk/wiki/Ma ... nd_Heating" onclick="window.open(this.href);return false;

Sounds like you're missing part of your cooling system so that explains the problem with your temp guage (but not your fan problem).

Do you know how long the previous owners had the van and this set-up in the engine bay?

Tony

[andyb]

are you fairly confident that it's a 1.9D?
looks like one to me and seeing as 1.9D engines from other VWs are the easiest to fit its a pretty fair assumption - to check you would need to look on the engine block and see whats stamped there - look for large numbers 1.9 or letters

why do you think it's not well fitted?
for starters there no expansion tank fitted to the water tank - your coolant is gonna just overflow and say bye bye - they havent bothered to change the oil dipstick for the t25 one and looks like the dipstick even although hasnt been changed is still leaking - a sysmpton one gets after changing them normally
were all original vw buses fitted with petrol engines?
no - there were 1.6D 1.6TD and 1.7TD s

as for the oil, yeah there does seem to be a leak unless as you say the gauge is unreliable and i've inadvertently overfilled it
if you do overfill a deisel engine you risk actually damaging it as bad or worse than no oil so be carefull - I would drain the oil and refill and measure the correct level - should take 4 litres with oil filter left in place.

the cooling system was actually overhauled shortly before we bought it and the hoses going from the engine to the rad are new
the fn problem - look for a short circuit which is bypassing the thermo switch - that would have fan running all the time

as for the engine lid, yes it fits fine and locks ok
happy for you as sometimes they a pain with alternate engines and the throttle lever gets in way

does anyone have any suggestions as to the best way to proceed from here to start eliminating possible causes and is there a way to tell if the engine is overheating regardless of what the gauge is saying?
very crude but try a electric thermometer in the water - and if you get fan fixed properly well that will give u an indication as it will only operate about 93 degrees centigrade or above.

[phil miller]

Its a 1.9 defo, mainly because VW never made a 2lt that looks like that

Second, you dont need the over flow, i didnt fit one in mine and have ZERO problems of coolant loss

Third, as long as your aware of the dipstick issue then all is well

Forth, the bay looks ok to me, im not an expert on cars tho........my day job is top tech in a VW Audi Indy so i dont think i know what im on about

Now for the fans, due to the engine change if you booked it in to our garage the first thing i would do is make sure the fan switch is working, the fan switch is a fail safe system, so if it fails it should kick the fan in (well its meant to) it could be someone has given the fan switch a batt live, that would explain the fan, it is also poss that the temp gauge wiring and fan switch have been combined, without testing its a job to tell

Hope this helps

[kit]

I thought the expansion tank and overflow tank were vital? It is defiantly a 1.9 and I would also be concerned about the throttle linkage it looks as though it could catch on the engine cover and I would check that dipstick very carefully.

[Oldiebut goodie]

Second, you dont need the over flow, i didnt fit one in mine and have ZERO problems of coolant loss

Given that 17 litres of water at 20 deg.c expands to 17.2 litres at 80 deg and that the engines tend to have water hotter than that so it will be a little more you must have super soft/flexible hoses that absorb that expansion without any water exiting the tank. Everyone else's seem to have the need to vent and draw back this expansion - what have you done to circumvent this? I am intrigued.

[phil miller]

Second, you dont need the over flow, i didnt fit one in mine and have ZERO problems of coolant loss

Given that 17 litres of water at 20 deg.c expands to 17.2 litres at 80 deg and that the engines tend to have water hotter than that so it will be a little more you must have super soft/flexible hoses that absorb that expansion without any water exiting the tank. Everyone else's seem to have the need to vent and draw back this expansion - what have you done to circumvent this? I am intrigued.

No soft hoses at all, it's a very easy thing to do when fitting a 1z, all newer cars have a sealed coolant system, this allows water to have a higher boiling point (as its under pressure) the mk3 golf has a sealed coolant system with no issue so when I fitted mine I allowed for this, like I said I have zero coolant loss, it doesn't over heat and has done over 700 miles with no issue, the 1Z has a header tank return all you need to do is use that no problems

But hey, like I said above I don't know much about Vdubs, as I've only been in the trade for 20yrs, mine works fine, and I'm sure other mechanics would be able to think there way round a very old fashioned coolant system an make it more reliable, that's all I've done

[Oldiebut goodie]

But you are talking of cars which have a much smaller capacity coolant system. I don't care if you have been dealing with vw.s for 100 years - you still cannot fly in the face of physics. Where does your expanded water go in your super system that you have apparently designed?

[phil miller]

But you are talking of cars which have a much smaller capacity coolant system. I don't care if you have been dealing with vw.s for 100 years - you still cannot fly in the face of physics. Where does your expanded water go in your super system that you have apparently designed?

The system works except it or don't makes no differnce to me, I haven't designed anything, just thought about it and used the same set up as newer cars, it's not for me to prove it works, all I can work from is my problem free system over 700 miles, the fact I don't lose coolant and I don't have over hearing issues, talk physics all you like but when coolant or water is under pressure that changes things a little, but then you know that, why do you find it so hard to believe that it works? Are you trying to say the 1Z in a golf will lose water?? It's not rocket science it's basic stuff tbh

PS I may look old but it is only 20 yrs lol

[ewenmaclean]

Hello,

I have the same system as Phil and trust his understanding of this stuff very much - especially having seen his work on his van. If you fill the coolant to the brim then indeed you will have coolant loss, but it finds its own level just underneath. I have never overheated or lost coolant, I mark the level on the coolant header tank once it's been up to temperature and that's where it stays. I just use a Mk2 golf coolant tank cap, but the dalek cap is fine too. The tdi are thermally much more efficient than the idi engines and don't get as hot, which does allow this system to work well as the fluid expansion is somewhere in the order of 150ml.

I know the aaz engine (for example) gets a lot hotter and so the expansion is a lot more, so it's possible this system wouldn't work as well and you would need and expansion/overflow tank. If you have a very efficient cooling system, and the van never gets above 90 degrees or so, then this system works. If you expect to get very hot then perhaps not.

Ewen