Another Overheating Thread,White Mayo!!

david burton · Post by **david burton** » Tue Jun 21, 2005 8:26 pm

disappointing news - although I'm surprised he did all of the other stuff before looking at the head.

so why the temp rise? does he think air is getting into the water system and that causes the spikes?

that's a real pain - when he was doing the cam belt he could have also done the head when it was all off. gutted.

jags53 · Post by **jags53** » Wed Jun 22, 2005 6:23 pm

yea thats what i was thinking,a shame.
hes not sure if it is the head,but he thinks the water is not flowing through the system,how it should be,and had checked everything else.

so can heads still fail,even after a compression test goes well?how accurate and what does this test involve?
and if so can the damage be that bad, if the test didnt pick it up?

also i dont seem to have no symptoms of a head failure.
no oil mix with water,no smoke from exhaust,no loss of power,and if a head does fail,does it happen suddenly?

im thinking im gona get a once check over from a vw specialist,before i make my next move.

david burton · Post by **david burton** » Wed Jun 22, 2005 11:41 pm

firstly - definitely get a second / third opinion on this

the guy has NOT been accurate, it's worth taking it somewhere else first.

the compression tests are not accurate enough - I had one done on my Megane and they said it was fine - a week later it blew the gasket. BIG mess. and they had to think about giving me a discount on the compression test when I took it back and said it was rubbish!

IIRC I think they test 3 things on a full test - one probe goes in a spark plug socket, not sure where the other two tests are done?

it sounds very peculiar. I wonder if it's sucking air in from somewhere else in the system.[/b]

KITT · Post by **KITT** » Thu Jun 23, 2005 12:48 pm

A compression test will only tell you if the cylinder bores are holding compression (i.e. there's no leaks). However, a head gasket is designed to keep the oil and water channels seperate from the cylinder bores. It can leak in many ways:

between water and oil (you get mayo)
between oil and cylinder bores (blue smoke)
between water and cylinder bores (condensation out of the exhaust)
between cylinder and outside (low/no compression)
between water and outsite (water everywhere)
between oil and outsite (oil everywhere)

So just because the compression check was good, doesn't mean there's not a leak from the oil or water channels. I suspect there's a oil/water mix as you mentioned mayo in the expansion tank.

Trouble here is it's got very hot and has probably distorted the head (easy to skim back flat). However, if you've cracked it then it's new head time. I'm not sure what the heads made of, but I'd be supprised if you've cracked it TBH.

Best of luck!

david burton · Post by **david burton** » Thu Jun 23, 2005 4:10 pm

^^^^ Good stuff that man. very useful.

jags53 · Post by **jags53** » Thu Jun 23, 2005 9:45 pm

Cheers for the kitt
very helpful
when i get time im gona get another garage to look at it.
i didnt get mayo in the end,it was a melted leaf/flower petal,that found its way under the bonnet,and the water/coolant made it look like mayo.

when left idle in my drive for about 10-15mins i get a lil bit of smoke(normal looking smoke) and a few drops of water from the exhaust.

99 · Post by 99 » Mon Jul 04, 2005 8:19 pm

Hi there.

Sorry if you've already tried this, but have you run it without a thermostat for a while? I had a similar problem (steady at 90 then all of a sudden 110+), removed the thermostat and it stuck below 70.

On mine it was the thermostat adapter that was broken, but I think you've already replaced yours?

Like I say, sorry if you've already been through this, just thought it could be an idea.

test_richie · Post by **test_richie** » Mon Jul 04, 2005 8:36 pm

right just seen this.

The prob you have got is what i had but you have made it alot worse by keep driving it and letting it over heat.

It sounded like it stated of as the water pump, which means the coolant was not moving round and staying in one place and heating up.

But you kept driving it and testing it has proberly warped the head, so you will now need head work done that can cost abit.

Things i would do to get it back on the road.

-Head work
-new water pump (think you have already)
-new thermostat and the housing
-new blue temp sender
-new head gasket
-and make sure you put brand new G12 plus coolant

Any questions PM me and i am happy to help.

Dave

jags53 · Post by **jags53** » Mon Jul 04, 2005 8:43 pm

cheers for that dave
this week im going to fit a new thermostat and housing myself,altho the garage guy said he did(only after i asked him),i dont believe him,and its only Â£40 or so.
if that fails goodbye polo as i cant be arsed to pay for a new head.

@99 cheers for the advice, im going to try that this week.

test_richie · Post by **test_richie** » Tue Jul 05, 2005 12:43 pm

jags53 you have PM

jags53 · Post by **jags53** » Thu Jul 14, 2005 11:01 pm

Update:
ok guys i didnt get around to fitting a new thermostat,or housing,but i took the existing one out,and the heater,along with the bottom hose,were hot after a while,whereas before with the thermostat in the bottom hose was stone cold.

so,im hoping this was the issue all along,so im going to fit a thermostat and housing over the weekend,but theres still a chance the heads gone

rameshsingh · Post by **rameshsingh** » Wed Jul 20, 2005 1:41 pm

dont sound too good mate !! anyhow, i got about 1.5litres of the febi red g12 coolant for my mk4 polo. sold the polo now, so if its any use to you, you welcome to come pick it up. HTH

jags53 · Post by **jags53** » Sat Jul 30, 2005 7:09 pm

cheers for the offer rameshsingh,but i've got plenty of the stuff in the garage lol.

ok so i finally got around to fitting my new thermostat and housing.
i had a look at the old one,and inside,it was all bubbled up,and there was a large rod/needle going through one end and coming out the other(could be from the old thermostat)and it was like a purble/brown colour,around the edge of the housing.looked knackered.

flushed the system including radiator,and refilled with new coolant.
drove it around yesterday about 8 miles and the same again today,and all seems fine at the moment,top hose hot and bottom hose gets hotter as the temp gauge raises to 90.i havnt got the fan to come on yet,as the weather seems to be cool,so i guess time will tell.car drives smooth as anything.

also is it normal for the coolant level to go down a very lilttle bit after one drive just after re-filling the whoel system,as i've had to top up a couple of times,but second time was very little.

test_richie · Post by **test_richie** » Mon Aug 01, 2005 9:13 am

Hi mate.

Glad to hear you have had some progress at last.

I would really get your head looked at tho. The amount of times it has over heated, will not have done it any good.

All it will need is a quick skim and a new gasket. Just to make sure it is nice and flat.

There must still be a leak, it should not go down that much, that quickly.

Dave

jags53 · Post by **jags53** » Mon Aug 01, 2005 6:30 pm

yea i was thinkin that also,its overheated alot of times.
done about 40miles now,and the coolant level had not seemed to have changed,since the say i flushed the system. so thats looks good,so ill guess time will tell.