White foaming in expanction tank vr6

[Big ash 3]

Hi peeps I think I have a big problem need some advice. I have a 1998 mk3 golf vr6 highline with 71k on the clocks Iv noticed the past week or so that it's loosing coolant and loosing it fast like it completely empty in just like 15/25 miles Iv got to fill it up tonight then turned it over with the cap off noticed level rose up past max kept it running and why it was getting up to temp ( had the heaters off) I noticed the was a white foam appearing then out the blue it would start to flow over the top of tank. Fans kept kicking on and off wen needed. I put heaters on full power and on hot and level went down to just below max. Put cap on and left running another 5/10min again fans came on wen they was ment to. Car runs sweet as a nut it doesn't miss a beet never over heated gets oil dropped and new plugs ect every 3/4months like I say it runs just as sweet as my 17 reg golf r

 

Please peep any ideas I think I no what it could (HG ☹️☹️) be but wanna see what other people say aswell

 

Many thanks ash

[RBPE 198]

Overflow is due to expansion, hence why they have overflow/expansion tanks (not sure of your knowledge on such things but seeing as you said HG I may as well lay it out for noobs rather than you as you prob don't need it!) - basically the atoms of certain things reverberating - in this case possibly water (hydrogen/oxygen H2O) molecules which leads to expansion. The cause of this is usually of course heat causing it, too much heat, the bane we don't want and a set temp under conditions which the factory deem safe for normal operation! Not only that but an over abundance of oxygen (adding air - i.e. a split causing the fluid to be replaced with air) can exacerbate the situation!

 

There obviously can be loss of coolant with a split in a pipe or loose clamp, if you struggle to see it, say checking under the car in the morning, then it's usually either collecting on something like the gearbox or any other housing/part of car, or possibly even just evaporating! So if you are struggling to pinpoint the source - and do take some time to see where it does come out, then this could be a reason!

 

Once you go through all the hoses and parts that carry the coolant mix about then it's off to the areas where they interact with the engine.

 

A well known area is, of course, the "crack-pipe" as it's known, quick search link;

 

 

Once this is done, or at least checked out,  which would sort a lot of those having coolant problems, then addressing the OP directly;

 

"Yeah, obviously check the seal area's to the engine if you've checked the external coolant carriers mentioned above including radiator of course, rubber seal areas can be prone to splits quite easily where they meet the engine first and foremost, be cheaper and easier checking/replacing easy seals, than cam cover/head off job of course - then yes - on to checking the gasket seals  - checking for any bits that have crumbled in terms of passageways or simply a split in the head gasket material causing an incorrect seal... you sound like you know what you are looking for in that respect!" and to any noobs, you need a nice, air-tight seal here as leaks will occur.

 

Sorry, had 20 mins to kill so thought I'd give an overview for any noobs but if you've checked the obvious and nothing, then yep, onto those gaskets I'm afraid!

 

P.S. It's also not uncommon to get a leak from the coolant sensor area with a bad fitment, have had my own "this part is correct" but just "quite" didn't fit correctly although it at first looked sealed, plus some who have converted their cars not fitting it correctly by accident/tightness - so another easy check there if need be if you changed any such things - usually carries some fault codes!  

[markhaywardbailey 3]

Hi there I've had similar issues with my mk3 vr6 with mayo in the expansion tank . In my case it turned out to be the oil cooler which is at the front of the engine . Not an expensive part to replace just a bit fiddly. I did however have a coolant leak in the side of the head so I had to replace the head gasket which had perished . I did the job myself on the driveway and did the water pump at the same time. It's not as hard as you might think there's a lot of info about if that turns out to be your issue . That said the vr6 engine is so well designed that mine never overheated on me even when the coolant warning lamp comes on and I had to stop and replace the fluids
Let me know how you get on
Mark

[markhaywardbailey 3]

Just another point to check ....vr6 has an auxiliary water pump which energises when you turn on the ignition . You should hear it whirring away ( it's sited on the right hand side of engine above the gearbox) mine had failed and I had to replace it. Also if your coolant seems to disappear then come back and overflow as mine did for a time then the thermostat could be at fault . I removed the coolant flange got it out and sure enough it did not open when immersed in boiling water . I replaced it with a higher temp rated one and after that I did not have any issues . If you do this job be sure to replace the coolant flange and all the gaskets ( it's about £25 from GSF )
Hope this helps
Mark

[Big ash 3]

Thanks for your advice like I said don't no if it is the head as Iv got nothing in the oil. But I have noticed that when the engin is switched off I no the auxiliary water pump still gose few min after. But I sat and looked and the return hose that gose back to the expansion tank at the top. I can see coolant still going round but also see the white foam with air bubbles init. If it was my head there shouldn't be any air in the system if the engin isn't on should it?

[markhaywardbailey 3]

Hi
When you take the lid off the expansion tank after engine is hot is pressure released ? If so you have air trapped in the system. There is a bleed screw at the end of the crack pipe which you can access from under the car at the front. Ultimately if there is a leak in your cooling system it introduces two problems 1. Loss of coolant 2. And what a lot of people don't realise is the ability of air getting into a closed system. Regarding the oil cooler it's quite common for the oil to get into your coolant rather than the coolant getting into your engine and this would explain the white foam . In my case the head gasket split at the left hand end of the head and was just dripping down the engine . Have you found any leaking point yet ? Any wet patches on the carpet on passenger side as this is where the heater matrix is ?
Mark

[markhaywardbailey 3]

[markhaywardbailey 3]

[markhaywardbailey 3]

Pics of my mk3 vr6 and my r32

[Big ash 3]

Yes when the engin as bin hot then cooled down I take the cap off and loads of air comes rushing out and the level rises up abit. I didn't no there was a bleed nipple on these cars for the coolant. I carnt see any leaks from looking around the top of the engine but I can leave car running in one spot for 15/20min and nothing on the floor under the car. It's doing my head in because I like my cars to be 100% lol

[MJ Vr6 79]

Mate, start with the easy stuff, replace your Cap first.. Get original than Copy. 

And see how you go.. 

 

If you are in thoughts of Head Gasket, just get a compression check done mate. 

 

 

 

[MJ Vr6 79]

On 15/06/2017 at 8:53 PM, markhaywardbailey said:

 

Fellow 32 owner!! ?