Damm temp gauge

[texasuk]

Driving me round the twist.

It started to report massive overheating while driving the other day, then went back to normal for a bit. Now whenever I get some speed up it reports that the engine is going into meltdown. Except it doesn't, everything carries on as normal and when I come to a standstill and it is at tickover it goes back to normal again. At first I thought it was an electrical fault, but the ability to reproduce the symptoms at will just by getting to speed tells me it is something else.
Does this sound like an air blockage? Is there a know situation where the sender does not have contact with the coolant and so reports a ridiculously high temprature? Can the sender be sending the wrong info, so that the gauge reads wrongly, even though when I come to a standstill it then reads normally?
I'm more inclined towards an air block somewhere, but don't really know where to start with it. I did take the bleed screw out of the rad while it running the other day, and no water came out, but the rad gets lovely and hot and the heater matrix obviously still has water in it as well. Is that normal?

Thanks in advance of all suggestions/ideas.

[Ian Hulley]

You need to bleed the system properly, otherwise you'll be able to tell nothing and your temp sender will die ... there's instructions in the Wiki.

When you undo the bleed screw in the rad you should have air until the coolant flows out. Then do the back end with the bleed screw open on the thermostat housing. I live on a hill so have never had this problem bleeding our's

Ian.

BTW you don't say what engine you have !

[ghost123uk]

Is there a know situation where the sender does not have contact with the coolant and so reports a ridiculously high temprature?

Actually it is the other way round.

When the sender has no coolant around it, it reads cold, when in fact the engine can be seriously overheating

This is "snipped" from another recent post of mine on this subject =

Suggest you get it bled properly before you drive it again.
(See = https://club8090.co.uk/wiki/Co" onclick="window.open(this.href);return false; ... ing_system)

Airlocks in these engines can cause serious "hot spots" that can do loads of (expensive) damage

Be careful with it and let us know your findings

p.s. - put the heater on and use your left knee to monitor the hot air coming out (from the outlet by your left knee) - if it varies as you drive, you have airlocks, if it goes cold, stop and check the engine temp, driving with it blowing cold when it shouldn't be is playing Russian roulette with your engine.

[ermie571]

Texas,
what is the flashing red light doing? Cos if that is flashing it is low on coolant.

Check in your engine bay that the tank inside and to the left is brim full, and that the header tank behind number plate flap is also full.

Em
x

[texasuk]

Thanks for the replies.

The red light is flashing as if there is not enough coolant, but when I go to check the tank is full up. Also it stops flashing when the engine is idling, and ofcourse the gauge also goes back to normal. The heater is blowing out lovely warm air the whole time, I would stop instantly if it was blowing cold as that is a sure sign of no water in the system.

I shall try a drain and refill, bleeding as mentioned in the Wiki. Do you have to have it idling quite fast when refilling?

[Ian Hulley]

Just ticking over will do but you do need to speed that up to force the bubbles out.

YOU STILL HAVEN'T TOLD US WHAT ENGINE IT IS !!

Ian.

PS Which tank are you saying is full up ? The one in the engine bay proper or the one behind the cat flat ?

[ermie571]

oh yes.....you need a fast idle - we have it at about 2000 - 2400 revs on the counter - this makes the water circulate faster and you get more water in.....then you have to wack the blue cap on before you let the revs drop or it empties out all over your feet!!!


Em
x

[texasuk]

It's a 1.9

It's too dark to do it on crappy bit of parking I have, I'll have to have a go at it tomorrow morning. Which is a pain because I really wanted to use it Sunday, and I have a lot to do tomorrow as well. Oh well. Thanks for the tip about getting the cap on quick as well.

The full up tank I am referring too is the one in the engine bay. Cat flap tank is at right level when cold.

[texasuk]

OK, managed to bleed the system today, it took 3 litres to fill up so I guess that is what it was missing. I assume that the heater matrix was performing the task of radiator and stopping the engine from actually going critical, but I hate to think of me cruising for 40 miles with the temp gauge that far in the red. Hopefully it won't of actually done too much damage.
Suffice to say that it runs beautifully now, takes a while to get heated up and sits just past the red light when at running temperature. Lot quieter as well, must be that water jacket. I think I need to get someone to help bleed it again, just to be sure that it has got all the air out. Running around the van filling a small jug up with antifreeze mixture, then running to the front, then back again a few dozen times entertained the neighbours.

I also could not find the bleed screw in the engine bay, it doesn't look like the drawings in my Haynes manual. I'll take a photo but maybe there is something missing?

So thanks for the help so far. Along with the new bigger wipers, the new heater fan switch, rubber for the clutch pedal and the Bi-Pot 30 that fits exactly to size under the buddy seat, today has been a good day. Lets see how she performs tomorrow, and that there is some nice surf!

[ermie571]

Well done!!!

I dunno if this is any help, but, if you wanna check it take it for a run with a flat head screw driver and the spanner for removing the rad bleed screw, and a plastic bottle of water.


get home, and park so the nose is slightly up. Whip the grill off, and crack the rad bleed screw. if it spits at you, there is still some air - leave it cracked until all air gone, and water runs down rad. Tighten, and put grill back. Round to back of engine, make sure number plate flap tank is full (add water if necessary). As the van cools, it will suck in water from the header.

do that the next couple of times you drive it upto temp......and you should be reassured there's no air in there. Just to really check, when the engine is cold...ie before you move in the morning, check both tanks for levels.

hope that helps

Em
x

[Ian Hulley]

When bled properly you'll know if you have a leak because the top up tank goes down. This time of year a 1.9 petrol running on petrol should be on or slightly below the red light on the guage.

You'll get the feel for these lovely old buses and know when something's not quite right they become a part of your being and you can sense it.

Ian

[CovKid]

Would concur with that - more so if you've owned a Type1 or Type 2. My temperature guage doesn't work at all for some reason at the moment but it runs fine and not using any water or oil.