Coolant steam from expansion tank

[kevinbowe2000 10]

Once the temp gets to 110c (which happens after about 20mins drive), loads of steam starts coming from the expansion tank. Got the t-stat replaced as seemed like the issue. Didn't work though. Fans work perfectly. Had new rad a little while ago. No mayo in the cap. Sniffer test was "inconclusive". Had a pressurization test and was fine. Really hoping that its not the head gasket but seems like it might be.

Anyone have any other ideas what to do before I fork out for a HG replacement?

[Jim 2]

Temperature shouldn't really be getting to 110 after 20 minutes driving. Is that coolant or oil temperature? What is the corresponding oil / water temperature when the other temperature gets to 110?

[g0ldf1ng3r 14]

Good point Jim - kevin, sounds like something is amiss as surely if the fans are 'working perfectly' they should be kicking in at all 3 stages [if vr6] to bring the coolant temp down :s

 

it might help others with offering advice if you state your engine model too kevin :)

[kevinbowe2000 10]

Sorry for not clarifying. Driving a vr6.

Yeah its the coolant temp reaching 110c which naturally just boils. Had anti freeze put in when flushed the system (removed any airlock etc).

Fans tested by just putting power to them when in garage. Also come on when car parked after driving.

Sorry didn't get oil temp. Was concerned about getting car to safe place before dying.

Thinking fans aren't coming on while driving?

[easypops 8]

Heaters ok? Can you see water returning to the expansion tank through the small return pipe?

[kevinbowe2000 10]

Just rang garage there. Says the fans are coming on :(

[easypops 8]

Could be the water pump?

[kevinbowe2000 10]

Water pump did look a bit corroded. Don't have the car in front me but will check the return pipe after lunchtime.

Guessing that if water is returning through small return pipe, then can conclude water pump is okay?

[kevinbowe2000 10]

That would then led to believe HG is the problem?

[g0ldf1ng3r 14]

Kev - whilst your engine is running & the coolant temp rises your fans should kick in at 3 separate stages once temp surpasses 95 ish degrees

there will be a thread on here which states what temps each stage kicks in

if the garage only tested fan operation by putting power direct to them it could point to faulty coolant temp sensors as this would explain why when the engine runs the temp goes out of control

the garage can easily test this by watching the fans as the engine is running & the coolant temp is rising

i think the fan over run is controlled by another separate sensor but im not 100% sure

[kevinbowe2000 10]

Many thanks for explaining. Newbie but trying to learn fast

[robrado974 1]

As gold says check out the ultimate cooling guide , everything is in there you need to know .

[Jim 2]

And make sure they are using genuine VW G13 coolant and not some aftermarket ****e! :)

[Dox 23]

When you say you've flushed it do you mean disconnecting coolant pipes and flushing the rad, block, heater matrix etc with a hose pipe?

 

Some antifreeze types don't mix and create a jelly like substance.

 

The main coolant pump is belt driven, there's an electric pump that should run for a short while when the ignition is turned off

[g0ldf1ng3r 14]

many of us on here like to help kev & there is quite a learning curve :)

 

what did the garage flush it with? IIRC im sure ive read that the VR block doesnt like coolant flushes due to some very small channels which are designed to move coolant round the block effectively, which some flushes can end up blocking

[kevinbowe2000 10]

Not sure what the garage flushed it out with or how they did it. Being very presumptuous in hoping they know what they are doing.

 

Read though the ultimate cooling guide so made up this plan of attack.

When I get car back from garage, ask them how they flushed it, what coolant they put in it and what anti-freeze.

Run Engine and listen for aux pump.

Check if water is returning to expansion tank through small pipe.

Rev engine to increase temp to check if fan comes on at stage 1 and maybe stage 2 dependent on results of stage 1.

Let engine reduce in temp til fans turn off, turn ignition off and try to listen for electric pump.

 

Think that should let me know everything?

Except the main water pump.

If the engine is reving higher, will the return flow rate to the expansion tank increase?

 

Many thanks for all the help. Really most appreciated.

[Jim 2]

It does reek of airlocks still I have to say. The VR can be a bit stubborn for getting all the air out of the system as I found recently changing the radiator on mine. The 16v was a lot less hassle for this.

 

After changing the coolant out of the car, I had to get it warmed up with the expansion cap off, and kept squeezing all the large coolant pipes to help force water round the system. It also took an age for the thermostat to open so you can't really get water moving around properly until then. I'd let it get to that point, and let it all cool down, then restart the car and kept doing it several times before letting it get properly warm and letting the coolant in the expansion tank start to steam and get a bit lively before putting the lid on.

 

And make sure you've got the blue coolant expansion tank lid, and not the black one :)

[kevinbowe2000 10]

Garaged said they spent a long time getting the airlocks out. Maybe they didn't get all the air out. Will give that a go to. Think I'll try the other steps first though to check. Don't want to burn the **** out of myself for no reason :)

Ta

[Dox 23]

A new coolant pump is around £45 and would be my next port of call, I've seen pics of them with no fins left to pump the coolant around.....

[GlosterOx 0]

Not sure what the garage flushed it out with or how they did it. Being very presumptuous in hoping they know what they are doing.

 

When I get car back from garage, ask them how they flushed it, what coolant they put in it and what anti-freeze.

Many thanks for all the help. Really most appreciated.

 

Surely if they've used the correct G12++ or G13 Coolant there is no need to put additional anti-freeze in?

 

Ian.

[kevinbowe2000 10]

Just brought for a short spin. City center traffic. Didn't get out of 3rd. Hit coolant temp of 100 and then I switched her off. Fans turned on about 93 or so. Oil temp was 102 when I turned her off.

Both feed and return to rad are very hot. Can presume tstat is working okay then.

Can hear aux pump working.

Can't see any flow back to expansion though, but could be wrong.

No one was there at the garage to answer questions about coolant etc.

[Jim 2]

Yeah - just to reinforce Ian's point about the coolant. You just need VW G13+ appropriately mixed with water (instructions are on the bottle), with no additional additives or anything.

 

Did the fans come on with the engine running or only after you turned the car off?

[kevinbowe2000 10]

Engine running. Once I saw them come on for stage 1. I didn't push it. Don't want all the coolant to evaporate again before I get her to a garage.

[kevinbowe2000 10]

Stupid question but if I have it ticking over parked, should I see coolant returning to the expansion tank? I thought I would but newbie :)

[Jim 2]

I'm really not sure what 'normal' behaviour is for this. I certainly saw it when I was trying to get air out of the system on my car, but I'm not sure once the system is free from air and running normally whether you get coolant returning to the header tank.