21 replies to this topic

[Gibbo1974]

Hi guys,

 

I have a weird overheating issue....

 

Car is a 2004 Turbo, standard.

 

she runs at a constant 85 when cruising in the daytime, 86 when spirited driving is happening and 84 at night or on colder mornings etc..

 

the coolant is at the MAX mark all the time but when she gets hot (ie sitting in traffic) the temp starts to rise into the 90's and the fan kicks in at about 93 and that keeps het in check.

 

all good and nothing abnormal right ?

 

OK so when I get out the car when she is in the 90 temp range the coolant bottle is full to the brim and coolant is dripping out the overflow.....

 

what to do or check?

 

any help advice welcome......

 

ta 

[WrightStuff]

What level is the coolant at when the car is cold ?

Its supposed to be level of the seam.

 

Btw my turbo fan comes on at 97 and off at 93.

[Gibbo1974]

Hiya,

 

i's bang on the seam when cold..

 

Yes I think mine does that too, on at 97 and off at 93, sorry wrong way round....

[Bargi]

Fans should kick in at 106 on standard map. Usually lowered with a remap or external temp sensor for fan. Does the expansion tank look old, yellow and maybe fine cracks all over it? Got the same and the tank was ever so slightly weeping. New tank and sorted. Sent from my SM-G920F using Tapatalk

[Gibbo1974]

Tank look very new, nice and transparent (ish) and no cracks......

[Mr Apex]

Your coolant system needs bleeding. You have air somewhere that is expanding with heat. 

[Nev]

At switch off your turbo is still very hot indeed. It has small water pipes to and from it. Static water in the turbo jacket will reach boiling point (even at 10 PSI of whatever). This in turn creates steam. The steam can create an air block and push water into the tank at high pressure. Hence you issue.

 

There is an electric water pump that is supposed to help with this problem. The ECU can switch the pump on when you switch the engine off. However, many of these pumps are now seized solid so they do not work.

 

I have fixed my sized pump and installed a manual over-ride swtich in the cabin. I turn this pump on, and I also have a manual switch to turn the fans on the radiator. With this solution, the problem is mostly remedied (by manual switches).

 

 

Edited by Nev, 16 June 2017 - 08:25 PM.

[Mattias]

At switch off your turbo is still very hot indeed. It has small water pipes to and from it. Static water in the turbo jacket will reach boiling point (even at 10 PSI of whatever). This in turn creates steam. The steam can create an air block and push water into the tank at high pressure. Hence you issue.

 

There is an electric water pump that is supposed to help with this problem. The ECU can switch the pump on when you switch the engine off. However, many of these pumps are now seized solid so they do not work.

 

I have fixed my sized pump and installed a manual over-ride swtich in the cabin. I turn this pump on, and I also have a manual switch to turn the fans on the radiator. With this solution, the problem is mostly remedied (by manual switches).

 

 

 

That pump is only circulating water from the block to the heater and back. The water only self-circulate trough the turbo from heat on low rpm's and engine off. So still important to do some cool down driving before shutting off to keep the turbo healthy. 

[Nev]

 

At switch off your turbo is still very hot indeed. It has small water pipes to and from it. Static water in the turbo jacket will reach boiling point (even at 10 PSI of whatever). This in turn creates steam. The steam can create an air block and push water into the tank at high pressure. Hence you issue.

 

There is an electric water pump that is supposed to help with this problem. The ECU can switch the pump on when you switch the engine off. However, many of these pumps are now seized solid so they do not work.

 

I have fixed my sized pump and installed a manual over-ride swtich in the cabin. I turn this pump on, and I also have a manual switch to turn the fans on the radiator. With this solution, the problem is mostly remedied (by manual switches).

 

 

 

That pump is only circulating water from the block to the heater and back. The water only self-circulate trough the turbo from heat on low rpm's and engine off. So still important to do some cool down driving before shutting off to keep the turbo healthy. 

 

 

Yes of course any 1/2 intelligent driver should warm down, and hopefully the OP is doing this.

 

I think the electric pump does help circulate the turbo water jacket indirectly by causing a slow circulation of water round the whole system. I know this because without it my own water tank will make a mess at switch off, but with both the pump and fan on the problem is 75% cured.

Edited by Nev, 16 June 2017 - 09:11 PM.

[Mattias]

I doubt that has to do with the turbo, probably just the reduced heat soak in the block and head. The reason I doubt it is that I couldn't see any circulation in the turbo return without revving the engine so can't see how that small pump would. Think of the flow in a closed system based on pressure differences and restrictions ie hose sizes etc.

 

[Mattias]

As a reference, this is my new cooling circuit and even with this 400W pump at lower then half speed there is no flow in the small line going from thermostat housing to the header tank.

 

[Mattias]

But as suggested check that the electric pump is working and bleed the system, also let the engine warm up with the cap off to let air out. Leave it running for a while at idle once hot with the cap off and then put the cap back on and go for a test run and see if the problem is solved. It might help to park in a slope and rotating the car every few minutes to aid the evacuation of air bubbles.

[Strugs]

Am I alone in thinking the OP doesn't have a problem at all? Normal temps when moving. Gets warm in traffic, fan kicks in, brings temp down. Is that not what's supposed to happen?  

[fiveoclock]

Am I alone in thinking the OP doesn't have a problem at all? Normal temps when moving. Gets warm in traffic, fan kicks in, brings temp down. Is that not what's supposed to happen?  

Yes but the expansion tank isnt meant to fill with coolant and chuck some out.

[Strugs]

 

Am I alone in thinking the OP doesn't have a problem at all? Normal temps when moving. Gets warm in traffic, fan kicks in, brings temp down. Is that not what's supposed to happen?  

Yes but the expansion tank isnt meant to fill with coolant and chuck some out.

 

 

Yes.. missed this bit: "[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]OK so when I get out the car when she is in the 90 temp range the coolant bottle is full to the brim and coolant is dripping out the overflow....."[/color]

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]Whoops![/color]

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]OP - no, not normal!!   [/color][color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;] [/color]

[ayresyy]

This could be as simple as replacing the filler cap to fix. They don't always hold the correct pressure when they get old.

[Johnboyhgt]

Hi guys,

 

I have a weird overheating issue....

 

Car is a 2004 Turbo, standard.

 

she runs at a constant 85 when cruising in the daytime, 86 when spirited driving is happening and 84 at night or on colder mornings etc..

 

the coolant is at the MAX mark all the time but when she gets hot (ie sitting in traffic) the temp starts to rise into the 90's and the fan kicks in at about 93 and that keeps het in check.

 

all good and nothing abnormal right ?

 

OK so when I get out the car when she is in the 90 temp range the coolant bottle is full to the brim and coolant is dripping out the overflow.....

 

what to do or check?

 

any help advice welcome......

 

ta 

 

The cooling system should maintain an air gap above the coolant at all times.

 

If this is not being maintained than you have 3 possibilities:

 

1 the coolant cap (pressure cap) is faulty and not holding the pressure

2 The expansion tank (coolant bottle) is split due to age and the air is leaking out that way, does it look brown and old looking.

3 the pressure cap is leaking because there is higher than normal pressure in the cooling system - ie boiling over.

 

 

My money would be that the expansion tank is duff - these are relatively inexpensive and available from autovaux and comes with the cap so rules out no 1 and 2.

 

John

Edited by Johnboyhgt, 20 June 2017 - 07:52 AM.

[Tibbles Stryker]

I had an astra when I was a boy, same symptoms, in the end when it was sitting outside my folks house after a drive out it went bang. A hose had blown. This turned out to be a pressure cap failed with age. My first shout would be this, hey they're cheap as chips from vauxhall. As soon as I bought my vx I put a new one on as a precaution, lesson learned.

[sam220T]

Your coolant system needs bleeding. You have air somewhere that is expanding with heat. 

Definitely this had it many times in the VX. Use the bleed nipples to help remove the air.

[Gibbo1974]

where are the bleed nipples ?

 

I'm too lazy to look it up.....;-)