Coolant Temperature needle and light

[ghost123uk]

Went to have a look at the engine bay and noticed that the header tank level had fallen back down to just above the MIN mark

Just popped back in to say that the header tank doesn't have a MIN mark The Top Up tank does of course. I mention this in case you meant the Top Up tank was going down in level during the test run of the engine, which would be odd because it should go up during engine running and down on engine cooling down.

2. The thermostat is buggered - it should open after a certain temperature and allow the fluid to circulate through the radiator

That looks like the one to me as water pumps don't just stop working at all, suddenly.

p.s. Just noticed you are in Portugal

[Roydini]

Hi folks, and thanks again for the very helpful advice and comments.

So, here is today's update:

I suspect that the reason you're topping up and level still drops is you have air in the system and it needs bleeding. If theres not enough there may not be much if any water in rad so it won't get hot. Firstly, follow this (keeping an eye on temperature):

http://wiki.club8090.co.uk/index.php/Co ... ing_system" onclick="window.open(this.href);return false; - 2,500 revs should annoy the neighbours a bit if you're doing it right. If its not revving fast enough you'll never bleed it.

Had a go at bleeding the system with the help of Simon Baxters guide. TBH I found it a little tricky to be in all three places at once -revving sufficiently from the cab, adjusting radiator bleed screw, checking header tank, and all the while keeping an eye on the gauge up front! I think I got all the air out, but not completely sure so I think I'll have another go at the weekend with the help of a mate - and after topping up the fuel a little

Good idea on checking to see if thermostat housing bolts will move. The other two bolts on the housing (10mm heads accessible from underneath) where the thermostat lives, will come undone ok if you decide to just fit a new stat. They don't seem to be subject to seizing.

Managed to get a 10mm socket on both the vertical bolt heads holding the housing on from underneath, as you say. just cracked them an 1/8 of a turn to see if they would move and it seems they will...the other two bolts from the housing to water pump however are a right bugger to get to. I managed to turn one of them but the other was really tight/possibly seized. Soaked it in PlusGas and will try again tomorrow.

Its worth removing fanbelt and checking for wear in waterpump - you'll feel it rock about if there is any. https://www.youtube.com/watch?v=LghNy400HzI" onclick="window.open(this.href);return false; - you'll only detect it with belt off. You can then decide if the best option is a complete overhaul as I show in the WIKI. Clearly replacing pump and thermostat (arduous as it is) removes that problem from the equation but no sense in changing pump if there is no real play in its bearings.

Good advice. I removed the belt and wiggled the pulley around. There is very, very slight play but not as much as in your youtube clip. Given the ease of removing the belt it might be interesting if anyone else with a 'known good' cooling system could check their pulleys and comment?

I think given the relatively small amount of play in the pulley, ghost123uk's comment about the unlikelyhood of the pump suddenly failing and the absolute nightmare you describe in the other post, I'm going to leave the pump on and exhaust all other possibilities. The thermostats are only 15quid from Brickwerks and I reckon the two vertical bolts will budge so once I'm 100% happy with the bleeding I'll start with that, assuming that hasn't solved the problem of course!

Chris (CJH) is about to do his

Good luck with yours CJH. Sounds like you are well prepared for any snags. I may yet end up doing mine too as a last resort so I will follow your progress keenly.

[Roydini]

Oh and one other small thing just for the sake of future clarity, my header tank - the one inside the engine bay with the pressurised cap, not the top-up tank behind the reg plate flap - does indeed have a MIN mark. It is roughly half way up the tank below the hose leading to the top-up tank and says "<MIN>" My tank is the old version however with the metal twist lock cap, not the blue or black 'dalek' style one. Perhaps this is the reason

[ghost123uk]

Oh and one other small thing just for the sake of future clarity, my header tank - the one inside the engine bay with the pressurised cap, not the top-up tank behind the reg plate flap - does indeed have a MIN mark. It is roughly half way up the tank below the hose leading to the top-up tank and says "<MIN>" My tank is the old version however with the metal twist lock cap, not the blue or black 'dalek' style one. Perhaps this is the reason

Ah, yes, I might be in error there then . My excuse is, I have never worked on the earlier cooling system with the metal cap

p.s. Just noticed you are in Portugal

p.p.s. And yet your avtar has snow on your van

[Roydini]

Haha! Yes! The snow was in Edinburgh a few years ago before I retired the van to sunnier climes in order to quell the onset of rust!!

[CJH]

Well "best laid plans" etc - my UPS parcel didn't arrive, so I haven't been able to tackle the main water pump/thermostat job. My bolts from eBay did arrive though, so I've had that metal water pipe off to repair the studs holding the alternator bracket on, which was the job that really needed doing.

The water pipe needed to come off to do this because it blocks access to the alternator bracket studs.



It turns out that those allen key bolts holding the water pipe aren't flanged after all - what I thought was a flange was actually a corroded on washer. So my new bolts and washers are identical. But actually, since access to these two bolts is good I went for Ralph's suggestion of using slightly longer bolts (M8 x 30) with hex nuts instead of washers. The thread length is then the same, and as Ralph suggested, it gives me another method of removing the bolts in the future if the allen key rounds them off.

[Roydini]

Shame about the late delivery CJH. Have to wait till next weekend? The nut and bolt configuration looks sensible and I'll bear that in mind if I get that far...

An update from yesterday tho: Managed to bleed the system properly following Simon Baxters http://www.brick-yard.co.uk/forum/bleed ... 8d.html%7C" onclick="window.open(this.href);return false; instructions to the letter. I found it much easier this time with the help of an assistant - my girlfriend - although this did mean no cup of tea when doing the hand over the heater bit as he describes

Now that I'm happy there is no air in the system I'm planning on running it for a few days this week to see if the overheating problems have gone away or not. During the bleeding process I lost a fair bit of coolant so my mix is well below 50:50 now so I plan on draining and flushing the system asap (this was overdue in any case). For the price of a new thermostat, temp sensor, radiator fan switch and header cap I think I'll replace the whole lot while the system is empty and cross my fingers about the water pump

[CJH]

I'll probably not get round to doing mine for a few weeks now. Next weekend would be the first opportunity to tackle the pump/thermostat, but I'm VERY wary about Ralph's warning not to start this job immediately before a trip. I think I'll just carry the replacement parts as spares on my hols.

I agree it makes sense to do parts of yours while you're drained down anyway, but note that the difficulty in fully draining the system works in your favour here - by disconnecting any part of the cooling system you won't lose as much coolant as you might think (I lost almost nothing doing that water pipe at the weekend), and note also that if you catch the coolant in a bucket you can just strain it through a paper towel in a funnel and pour it straight back in. Worth remembering once you've got the 'good stuff' in after the flush.

[Roydini]

Well I think I've finally got to the bottom of this problem!

I was changing the gearbox oil (Comma GL4 80W90) today which had been on my list for ages and after going for a decent spin to get the oil warm before draining I noticed a small leak from one of the front-to-back coolant pipes. There was no visible dripping which was what stopped me from identifying it earlier, infact it was only from right underneath whilst undoing the gearbox fill plug that I noticed it. I've seen people mention this before on other threads but it seemed that the coolant was leaking out, but almost immediately evaporating, leaving no telltale drip on the ground.

So, some advice for anyone who seems to be losing coolant or suspects a leak somewhere in the system, you really do need to get right underneath on your back and check all the pipework. I recommend doing this after a decent drive when the system is pressurised BUT be very careful and wear good overalls, gloves and safety specs just in case. Remember that engine, gearbox, exhaust and coolant pipes will be hot!

So it seems I need to replace the front-to-back pipe work which is fair enough really as it is very corroded in places - OBVIOUSLY!! Lot's of places seem to supply stainless kits including both pipes, can anyone recommend a particular supplier? I read through the Wiki and it sounds like a fairly big job as the fuel tank needs to come out in order to get the pipes in and out. Anyone got any words of advise who have done this job before?

[xpress]

When I do a corner sometimes the coolant light flashes on but the needle is below mid!

[ghost123uk]

When I do a corner sometimes the coolant light flashes on but the needle is below mid!

Needle measures only the temperature, light measures coolant level and excess temperature

[xpress]

I always check the level! Seems ok to me still going strong!