running temp issues

[tubbyG]

evening chaps...

I went for a little blast after work tonight out the back roads, and while booting it from 3rd to 4th I noticed the temp shoot up to near the 3/4 (10 o'clock) so as I slowed to pull in it crept slightly past it :-(

I had a look to see if my fan had become unplugged- was plugged in, and when I bridge the wires it came on.

I looked for any coolant leaks- none, but the top rad hose was solid, and header tank looked full, released the pressure and the level dropped. then bled the system.

Then let it cool down before starting again. When I did start it I bridged the fan wires so it was running constant but the temp was rising
crawled home with the temp sitting at the 3/4 mark all the way, not dropping or rising.
I don't know whether my temp sensor in the head is fecked, fan switch is fecked, or I have an airleak in the system causing high temps.

Any thoughts?

[jamie_clioGTT]

sounds like an air lock to me, also check your alternator belt isn't slipping.

[tubbyG]

Should also add that I lost the bleed nipple from the top rad hose so I have bodged it with a small bolt. I used a spanner to nip it up so may have disturbed the seal

[juha5gtt]

New poster! (less than 10 posts)

Can also be stucked thermostat or radiator etc. I got same kind issues last year keeping constant 3/4 temperature.
I checked all pipes and changed thermostat..well didnt worked until i change my 23 year old o.e radiator to new one.

[tubbyG]

Cheers, I never thought about the alt belt.

I have a free weekend so will do some proper investigating.

But I'm curious as to why the fan didn't come on with the temp so high, after bleeding it twice could there still be air in the water pump, right at the temp sensor?

[R5MJH]

hope it aint hg mate this also gives these symtoms

[Tony Walker]

the temp sensor doesnt tell the fan to operate. theres a temperature fan switch in the rad this switches the relay that operates the fan. if the rad isnt bled properely then the fan wont operate correctly, check the whole rad is getting hot while running and try to bleed the rad with the bleed screw that is the other side of the thermostat.

[Nottswoody]

Mine had an air lock for a while they can take a bitch to get out.. Drake the inter cooler off lift up the bottle high as you can undo your bleed screw and the water will flush the air out.. Simples.. When running do the spit test round the screw see if its air tight..

[jamie_clioGTT]

because your temp is taken from the head and water temp for fan ON is taken from elsewhere, so if water is not flowing properly to the head it will get hot but the water will stay cool so fan wont come on.

[tubbyG]

hope it aint hg mate this also gives these symtoms

Me too


Shouldn't be though as I am running a bit rich @wot after turning the boost down. and also have a little retard in the ignition till I get it checked.

[tubbyG]

just been out and had it running, when loosening the rad top hose bleed bolt, the hose flexed and I could see a few bubbles and a very small bit of coolant coming from under the bit where the bleed nipple screws into so fingers crossed it will just be a case of sealing this up and bleading again

[TNT ANDY]

1st things first remove the fan switch in the radiator and check to see if this switches when dropped in boiling water.

2nd - remove both pipes to the expansion tank and flush it back and forth many many times until you get clear water coming out of both pipes in both directions, do this with the heater controls turned to hot.

Go from there.

[R5MJH]

if you rebleed as notts says check both hoses get hot then after it can only be fan switch or hg mate

[Tony Walker]

Dont presume headgasket, if the gasket was gone the system would be pressurising and the pipes would be pretty hard. The rad could be blocked, thermostat could be stuck, waterpump belt loose, waterpump goosed, rad fan switch, rad fan relay air lock, leaking rad so the switch isnt incontact with the coolant(doesnt matter how much you bleed the system, if the rad has a leak then its gonna drain out and not switch your fan on, even if the fan comes on itll be airlocked and wont cool)

[GT Josh]

Don't think it's your hg pal. Is the coolant system pressurising??

Didn't read Tony's comment lol sorry

[R5MJH]

Dont presume headgasket, if the gasket was gone the system would be pressurising and the pipes would be pretty hard. The rad could be blocked, thermostat could be stuck, waterpump belt loose, waterpump goosed, rad fan switch, rad fan relay air lock, leaking rad so the switch isnt incontact with the coolant(doesnt matter how much you bleed the system, if the rad has a leak then its gonna drain out and not switch your fan on, even if the fan comes on itll be airlocked and wont cool)

he did say the top hose was hard mate obviously yes it could be many things this is my option anywayz

[youngscottie]

Time to give your car a blow job
Remove the header tank cap and blow into it until its under pressure
Then open the bleeders one at a time till no air left
Only way I could get the air out of mine
Looks a bit strange but works a treat

[tubbyG]

when I first stopped it was initially pressurised, removed the lid to release some presure and was not pressurising again after that or for the 4 mile limp home. perhaps it was air getting into the system via the dodgy bit (where the nipple screws in) when I gave it some stick.

I was not losing any coolant, or seeing any mayo in rocker/ oil in coolant, or smoke from the exhaust.

I had flished the rad and all pipes when I built the engine in feb/march, always coolant - hopefully not corroded that much in 1600 miles use.

my header tank is in the scuttle panel and I usually just lift it as high as it can go then loosen the bleed screws, I hate giving it a blow!!!! It tastes horrible!

[TNT ANDY]

No need to blow in it - just raise it as high as it will go. We've got 1 bar of pressure pushing down on us at all times (dependant on the position of the moon and our altitude of course)

[tubbyG]

Im going to remove the top hose and try and repair the bit the nipple screws into to make a better seal, any tips on doing so?

with a bit of force, does it just pop out? I was thinking of just using a decent quantity of silicone and refitting

[ALI 786]

My money is on the Fan RELAY/WIRING as you have already confirmed the fan works when bridged...

Try fiddling about with the wiring / tapping the relay when TEMP is sitting HIGH, if fan comes on then you have found your fault....

Can also check Fan switch itself by boiling in pan of water indoors to see if it opens... BUT my money is on the fan RELAY / wiring.... [Located next to headlight / alternator]

[TNT ANDY]

He's bridged the stat out. The fan ran. The relay is good.

[Brigsy]

Is the water pump circulating the coolant? Check its returning to the bottle? Thermostat stuck? Even if rad fan isnt working it should run cooler when driving.

This reminds me of when i partially blown a headgasket and the car would get hotter and hotter until it chucked coolant out of the header tank, cooling system was pressurising and fan wasnt working but there was nothing wrong with it.

[jamie_clioGTT]

mate.... i hate throwing negative waves around, i really do but, bleed your system up and go for a spin with NO boost. if the problem dosent arise it will be your headgasket same happened to mine. no symtoms other than pressurising under boost.

[Flight666]

The best method I have ever used on my 5 for bleeding the system is to use an old expansion cap drill a hole in the top that is a snug fit for the valve from a cycle inner tube,cut off the valve and super glue it in the hole.Fit cap onto expansion tank pump up with a hand pump till top hose feels hard then undoe each bleed screw in turn quick rush of air until the coolant squirts out,takes 30seconds to do and works a treat saves faffing around especially if you are on your own doing the job, and you know its bled properly..

[tubbyG]

Thanks for all the replies.... Except the ones mentioning the headgasket

I do not have a thermostat fitted so that's ruled out. I will get stuck into it tomorrow and go through everything mentioned. I'm praying its just a slight leak on the top rad hose. if I can seal it properly and bleed again, hopefully it cures it!

Cheers

[Brigsy]

Id be tempted to do a sniff test on the coolant for exhaust gasses mate. Shouldnt be getting hot with no stat.

[LiamR]

The best method I have ever used on my 5 for bleeding the system is to use an old expansion cap drill a hole in the top that is a snug fit for the valve from a cycle inner tube,cut off the valve and super glue it in the hole.Fit cap onto expansion tank pump up with a hand pump till top hose feels hard then undoe each bleed screw in turn quick rush of air until the coolant squirts out,takes 30seconds to do and works a treat saves faffing around especially if you are on your own doing the job, and you know its bled properly..

Totally agree

[GT Josh]

Oh and just because you have good fuel doesn't mean your not getting any detonation.

[tubbyG]

Oh and just because you have good fuel doesn't mean your not getting any detonation.

I get ya bud, I understand there are a few factors which can result in det. hence using an adjustable tdc sensor at full retard to try and possibly eliminate one of these untill I get it checked.

[GT Josh]

Do what Brigsy said. Take it to a garage get them to do a sniff test and that will tell you for definite. Peace of mind! Plus you don't have to faff about snogging your expansion tank

[tubbyG]

spent a few hours this morning trying to the to the bottom of this,

removed the top rad hose and repaired the bleed nipple housing, flushed the coolant system, refilled and bled twice.

Let it run to see what the temp was doing and re-bled again - temp was rising slowly, as normal. But as soon as it got to the 1/3 mark the temp rose quicker and past the fan cut in point. Checked the coolant hoses for heat and they were warm, but not as hot as I would expect nor were they solid.

So I removed the expansion tank lid and I could hear the pressure escaping but then the water level rose within the tank almost coming out the top before settling down again ....... bugger!

So is this pretty much pointing to h/g failure?

[R5MJH]

spent a few hours this morning trying to the to the bottom of this,

removed the top rad hose and repaired the bleed nipple housing, flushed the coolant system, refilled and bled twice.

Let it run to see what the temp was doing and re-bled again - temp was rising slowly, as normal. But as soon as it got to the 1/3 mark the temp rose quicker and past the fan cut in point. Checked the coolant hoses for heat and they were warm, but not as hot as I would expect nor were they solid.

So I removed the expansion tank lid and I could hear the pressure escaping but then the water level rose within the tank almost coming out the top before settling down again ....... bugger!

So is this pretty much pointing to h/g failure?

i said that at the beginning sounds like it is then boss

[tubbyG]

i said that at the beginning sounds like it is then boss

I know

a lot of comments were pointing in this direction....... I just didnt want to believe it

[Nottswoody]

nothing to worrie about bud it will cost around £100 at most to fix i was worried untill i did mine.. £25 for skim £35 for hg £11 for bolts and a few beers for someone to help you...

sorted.. up and running by wednesday

[soapymech]

I know

a lot of comments were pointing in this direction....... I just didnt want to believe it

I Was in the same position a couple of months ago,what confirmed it for me was a sniff test which went from blue to green within a second of starting the car.

[tubbyG]

hold on....Ive just went and removed the coolant pipe from the top of the turbo and started it up..... there was no water being pushed out the hose or the turbo unless I squeezed the top rad hose

If the water pump was operating correctly I would have thought that coolant would have been pissing out??

[tubbyG]

nothing to worrie about bud it will cost around £100 at most to fix i was worried untill i did mine.. £25 for skim £35 for hg £11 for bolts and a few beers for someone to help you...

sorted.. up and running by wednesday

I know, a pretty easy fix... just annoyed as its not long back together

[tubbyG]

I Was in the same position a couple of months ago,what confirmed it for me was a sniff test which went from blue to green within a second of starting the car.

I am too scared to drive it down to a garage to get this done

[Nottswoody]

mate i drove mine for two months like it just keep an eye on the temps

[tubbyG]

mate i drove mine for two months like it just keep an eye on the temps

once it gets past the 1/3rd mark, the temp shoots up pretty rapid so dont want to risk further damage.

I am searching for the closest garage garage to me that can give it a sniff as we speak

[Nottswoody]

have you tried taking the alternator belt of and seeing if your waterpumps any good? mine just gave way one day. when i change my head i will always put a new one on just to save time later.. for £30 its not worth being sat at the side of the road like i did last time..

[tubbyG]

without taking it off, how would I know if the waterpump is any good or not?

[Nottswoody]

well mine failed at the seals at the wheel and was very loose im not saying that it will be that im just saying mine was a part of my hg problem..

[soapymech]

without taking it off, how would I know if the waterpump is any good or not?

With regards to the sniff test explain the prob maybe one of them will come out to you or even let you borrow it, or there's ones on the bay for 40 quid. I'm sure you can inspect the wheel inside the pump through one of the holes at the top, take the belt off and try moving the wheel side to side then spin it and listen for bearings.

[Tony Walker]

Sniff the coolant yourself does it smell of petrol? If you take the hose off the top of the pump then rev it a little should shoot water over your windscreen :-) carefull it'll be hot.

[Jonny5]

without taking it off, how would I know if the waterpump is any good or not?

A knackered water pump usually rumbles and sounds very noisy/rough when turning.May show other signs too.

[tubbyG]

Removed the top water pump hose (degassing pot one with the bleed screw) no water shoots out, unless I lift the header tank up high. Even then It just flows out rather than shoot out.
Removed alt belt and when spinning the water pump wheel it doesn't spin all that freely, there is no play but has a fair bit of resistance on it so stops it spinning pretty quickly

[andybond]

I would also get a stat installed.

[tubbyG]

new waterpump and stat ordered, I will hold off buying a hg untill I can rule everything else out.

Ive never had a stat fitted for the 3 years ive ran it, and had no issues