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1.9 engine odd behaviour

Printed From: The Brick-yard
Category: T5 Section
Forum Name: T5 Chat
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URL: http://www.brick-yard.co.uk/forum/forum_posts.asp?TID=94368
Printed Date: 29 Mar 24 at 06:08
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Topic: 1.9 engine odd behaviour
Posted By: Steve the boy
Subject: 1.9 engine odd behaviour
Date Posted: 09 Feb 20 at 21:53
Hi all.

I wanted to ask about something that is happening to my 2006 1.9 engine. It's done 147k miles, been serviced annually and looked after. 

It has a white residue in the rocker box, head gasket ?, but I'm not loosing water though.

What is happening though is that my temp gauge, usually rock solid at 90deg seems to dip a bit when sat on tickover for a while in traffic, then picks up again.

This has been happening since the timing belt and water pump change last may, but it's only in the  last few weeks that the residue is in the rocker box. Back in November I had the thermostat changed which seemed to fix the temp gauge for a while, but it's doing it again.

After the water pump change, we also got a "gurgling sound" from the engine about 4am when we camped in the van on days that we drove it (didn't do that before).

I have a couple of theories....

1. The water pump is cavitating and creating bubbles in the system around the temp sensor. Explains the Temp gauge and gurgling but doesn't explain the white residue.

2. I've actually blown the head gasket and filling the water system with air from the engine. I'm wondering if due to air building up in the system it can't vent into the expansion tank and so it can't release water into the engine, hence it looks like I'm not loosing water.

If you've got this far, thanks and have any of you seen anything like this.

 Thanks in advance for your replies




Replies:
Posted By: Charlie Dog
Date Posted: 10 Feb 20 at 10:19
Does your residue look like mayonnaise Sreve?

In the old days, mayo was mainly caused by: -

A blocked crankcase breather.
A slightly leaky head gasket.
Too many short journeys.
A faulty thermostat.

I also suggest you have your valve timing checked.


Posted By: Steve the boy
Date Posted: 10 Feb 20 at 21:43
Hi Charlie. 

Thank for your reply. I would say it looks more like semi skimmed milk. Not as thick as mayo. Would it get that thick (I've seen some YouTube videos of nasty thick mayo) quickly ?

It's going in for a core check at the local vw specialist that happens to be Rob d the corner from where I work. They mostly do T4 and T5 repairs so hopefully have seen most things that could go wrong. 

I'll keep this updated

S


Posted By: Charlie Dog
Date Posted: 10 Feb 20 at 23:55
Mayonnaise was a handy terms to 
that described it fairly well.

It started of thin, and then got thicker.
I haven't a clue how long it took
to get from thin to thick though.

Good luck with your VW specialist,
The man on the spot always does better
than the man watching a computer screen.



Posted By: Charlie Dog
Date Posted: 11 Feb 20 at 10:15
Originally posted by Steve the boy Steve the boy wrote:

Hi all.


What is happening though is that my temp gauge, usually rock solid at 90deg seems to dip a bit when sat on tickover for a while in traffic, then picks up again.


Have you got an oil temperature gauge Steve?

If so, how does it behave?

Most modern cars have a heat exchanger
that warm the oil up.
Usually, warm oil helps stop mayo.

The oil heater cooler sits
under the oil filter usually.

Mayo comes about because
exhaust gases get past the pistons.
The exhaust gases contain water.

That water condenses in cold crank cases,
gets mixed up with the oil mist
thrown up by the whirling crank.
The mix is sucked up to rocker box
where it condenses on it.

You spoke about a gurgling sound.

Could it be that 
when they changed your water pump,
they stopped flow through your oil heater cooler?

Note, the water in your mayo 
is probably from piston blow by.

Not from a block leak.
Which explains why 
you are not loosing water.

I think it would be a good idea
for you to check the temp
of the under filter heat exchanger
before you throw good money
after bad.

When I remember the fancy name
for that heat exchanger,
I'll post a piccy.

Unless some kind soul beats me to it please :o)



Posted By: Charlie Dog
Date Posted: 11 Feb 20 at 12:47
Modine :o)

Modine Donut oil cooler.

Pics here.
https://www.google.com/search?q=vw+t5+oil+cooler&sxsrf=ACYBGNSA3vl5hWAz4ZxNk5cZbkHe0eofZA:1581416369833&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiz3dyHo8nnAhUSYcAKHZqEBkQQ_AUoAnoECAwQBA&biw=1067&bih=458" rel="nofollow - https://www.google.com/search?q=vw+t5+oil+cooler&sxsrf=ACYBGNSA3vl5hWAz4ZxNk5cZbkHe0eofZA:1581416369833&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiz3dyHo8nnAhUSYcAKHZqEBkQQ_AUoAnoECAwQBA&biw=1067&bih=458

Personally, I'd bleed that Modine 
before I looked anywhere else.


Posted By: Steve the boy
Date Posted: 11 Feb 20 at 21:38
The results are in and it's early days of a blown head gasket, tests show exhaust gas in the coolant, but only a little. Trusted mechanic so I've got 4 options.
 Fix head gasket but might need the  block skimming too.
 Recon engine
 Second hand engine (if we can find one)
 Chemical sealant.

Before spending between £1k and £2k I'll try the steel seal and hope that it works.

Thanks for helping



Posted By: Charlie Dog
Date Posted: 12 Feb 20 at 08:00
Thanks for giving us the low down Steve.
Not nice for you.

Please let us know how you get on with steel sealant.



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