Coolant problems

[Trollhunter]

Thanks all for your help! Even though I’m having problems, I’m loving learning more about the van and what I can do myself!

I will drain a larger amount of oil to be sure. Also thought about topping up the coolant reservoir and running the engine to warm and increase the pressure, that way I guess an external leak should be more obvious. I haven’t noticed any smell with the heater other than an old sock smell, but this seems to have disappeared after I changed the blower fan (the old one was knackered) and pollen filter... I don’t think the previous owners ever disinfected the air system!

 

[Trollhunter]

With a bit of searching on the web I see that if the head gasket is blown, coolant can enter the combustion chambers and burn out with the exhaust. I see one test is to open the radiator cap and start the engine to look for bubbles. Is this the blue cap on the coolant reservoir? Am thinking this could be a good last test try.

 

[VW Guru]

Hi @Trollhunter which engine do you have ? The only time I’ve ever had head gaskets go is on the 1.9pd engines 7-8 chassis.

 

[TripleBee]

You could also test it by pressurising the coolant circuit overnight, and start it in the morning. If the exhaust starts fuming white smoke, it might be the head gasket.
The only problem is to get the coolant circuit under pressure without the right tools.

Or you could go for a test drive, going quite high revs, getting the engine very hot, and then CAREFULLY open the cap of the coolant reservoir. Normally the coolant will start to boil, rising very fast, even boil over the reservoir, this is normal. When you open the cap, and the coolant really cooks over very heavily, then this would also mean a head gasket, or a cracked head or engine block, causing the coolant to enter the pistons.

Don't want to scare you, but those are some of the possibilities, if no external leak is found.

 

[TripleBee]

Hi @Trollhunter which engine do you have ? The only time I’ve ever had head gaskets go is on the 1.9pd engines 7-8 chassis.

As it is 174 hp, it's the 2.5.

 

[Trollhunter]

As it is 174 hp, it's the 2.5.

Yes it is the 2.5

 

[VW Guru]

I had missed that it was 174 probably due to lack of sleep. Whe most common cause of coolant loss was the coolant pump on the 174 and 130 5 cylinder engines as it’s internal it leaks straight down the gear housing at the rear of the engine into the sump. Normally if this is happening then you will get coolant run out of the sump first when you remove the sump plug. The pump was always the most common cause

 

[Trollhunter]

I had missed that it was 174 probably due to lack of sleep. Whe most common cause of coolant loss was the coolant pump on the 174 and 130 5 cylinder engines as it’s internal it leaks straight down the gear housing at the rear of the engine into the sump. Normally if this is happening then you will get coolant run out of the sump first when you remove the sump plug. The pump was always the most common cause

Thanks, I have checked the oil from the sump and there were no signs of water. Took out a cup and have let it stand a few hours and no splitting of oil/water there either. Also no milky residue on the oil cap or dip stick. Thinking if I run the engine with the blue cap off I should see bubbling in the expansion tank if there are exhaust fumes getting in?
Engine runs well otherwise with plenty of power and I have not noticed any white smoke from the exhaust, other than occasionally at start up when its really cold.

 

[WelshGas]

Thanks, I have checked the oil from the sump and there were no signs of water. Took out a cup and have let it stand a few hours and no splitting of oil/water there either. Also no milky residue on the oil cap or dip stick. Thinking if I run the engine with the blue cap off I should see bubbling in the expansion tank if there are exhaust fumes getting in?
Engine runs well otherwise with plenty of power and I have not noticed any white smoke from the exhaust, other than occasionally at start up when its really cold.

Exactly when are you noticing the Coolant Loss.
With a Cold engine?
What happens if you run/drive the engine until upto normal operating temperature and then check the level? Has it dropped or risen in level in the Coolant Reservoir.?

One simple possibility that should be ruled out is the Coolant Tank Pressure Cap failing to hold pressure.
If this cap fails to pressurise the system then Coolant can be lost that way as the Coolant volume/temperature can increase and the excess will be lost via cap and when the engine cools the coolant level will show a loss.

 

[Trollhunter]

Exactly when are you noticing the Coolant Loss.
With a Cold engine?
What happens if you run/drive the engine until upto normal operating temperature and then check the level? Has it dropped or risen in level in the Coolant Reservoir.?

One simple possibility that should be ruled out is the Coolant Tank Pressure Cap failing to hold pressure.
If this cap fails to pressurise the system then Coolant can be lost that way as the Coolant volume/temperature can increase and the excess will be lost via cap and when the engine cools the coolant level will show a loss.

Yes I have noticed when cold. After driving I have come back to the parked car and on start-up the light on the dash has come on making me aware of the problem. That is a great idea to test, I have ordered a new cap already this morning I guess I should have noticed coolant around the outside of the reservoir if it has leaked there, but I can cross my fingers and hope it is this simple.
I think I will go for a drive after work to heat the engine and see if the coolant level changes, I guess a rise in level as you say could then indicate a potential failed cap?
Seems like its a good idea to test as much as possible before taking it in anywhere so I can save paying for someone else to do the same... even though its a pain in the backside, its kind of fun playing detective!

 

[Trollhunter]

Exactly when are you noticing the Coolant Loss.
With a Cold engine?
What happens if you run/drive the engine until upto normal operating temperature and then check the level? Has it dropped or risen in level in the Coolant Reservoir.?

One simple possibility that should be ruled out is the Coolant Tank Pressure Cap failing to hold pressure.
If this cap fails to pressurise the system then Coolant can be lost that way as the Coolant volume/temperature can increase and the excess will be lost via cap and when the engine cools the coolant level will show a loss.

Just out of curiosity, if the coolant is rising and getting lost due to a faulty cap, is there an overflow tube somewhere or would it literally flow out through the cap and all over the reservoir?

 

[TripleBee]

Just out of curiosity, if the coolant is rising and getting lost due to a faulty cap, is there an overflow tube somewhere or would it literally flow out through the cap and all over the reservoir?

There should be one on the underside of the reservoir, somewhere...

 

[TripleBee]

Or at least in the newer ones.

Try to put some water in the thread section of the reservoir. See if the water runs down, or if it overflows on top.

 

[Trollhunter]

The plot thickens! Have had the car in for a pressure test on the cooling system today and they cannot find any sign of a leak. Gonna leave it on pressure over the weekend to see if there could be a micro leak as they called it, just to be sure. Maybe good news, but still a mystery as to where I have now lost 1,5litres of coolant in the past couple of weeks. Got my new cap in the post so gonna slap that on after the weekend and see if it does the job!

 

[TripleBee]

Keep us updated?

 

[Perfectos]

The plot thickens! Have had the car in for a pressure test on the cooling system today and they cannot find any sign of a leak. Gonna leave it on pressure over the weekend to see if there could be a micro leak as they called it, just to be sure. Maybe good news, but still a mystery as to where I have now lost 1,5litres of coolant in the past couple of weeks. Got my new cap in the post so gonna slap that on after the weekend and see if it does the job!

A “micro leak” on a cold engine would become a leak on a warm engine

I have see this on Audi where no fault reported on pressure test cold



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[Trollhunter]

A “micro leak” on a cold engine would become a leak on a warm engine

I have see this on Audi where no fault reported on pressure test cold



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Thats an interesting point! Do you know if it is it possible to carry on the pressure test with the engine running?

 

[Perfectos]

I don’t believe the pressure test is possible whilst the engine is running, although most definitely possible when the engine has reached temperature. The Audi in question had a smell of coolant that could not be traced,although it was there, Audi check the car three months from the end of the warranty, could not find anything at all. Less than 1 month out of warranty, when the vehicle was returned, they miraculously found that the head had a “micro crack”. They tried to quote for a new head, only for me to point out they failed to find the fault within the warranty period, despite having dismissed the issue within warranty, very long story short, new head FOC.

Keep a good record and ask for the attempts to find the issue & the findings of the work shop investigation in writing., so you can show the history of the issue and failures to find it, despite it being evident to you the owner for some time,



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[Trollhunter]

Thanks, that's a good point to keep documentation, then I can at least maybe save a few pennies if I have to take it in again
Im not sure if they have removed the glow plugs or not whilst running the pressure test. After reading a little about it on the web this seems like something they should do if it is the head gasket they are looking at and not a leak elsewhere.

 

[Trollhunter]

Pressurised system over the weekend and low and behold about 700ml coolant missing from the expansion tank. The garage have checked for leaks in and around the whole vehicle and find nothing. Checked front and rear heaters too.
They don't suspect the head gasket due to the lack of excessive white smoke and the way it started and runs after such a loss.
Im wondering if the EGR cooler could be the place to look? Does the 2006 t5 2.5 have one? If so how can I check it easily?
I am also going to buy a block tester to see if exhaust fumes are in the coolant to be sure, but if the EGR cooler is leaking, would this also give fumes in the coolant?

 

[WelshGas]

Pressurised system over the weekend and low and behold about 700ml coolant missing from the expansion tank. The garage have checked for leaks in and around the whole vehicle and find nothing. Checked front and rear heaters too.
They don't suspect the head gasket due to the lack of excessive white smoke and the way it started and runs after such a loss.
Im wondering if the EGR cooler could be the place to look? Does the 2006 t5 2.5 have one? If so how can I check it easily?
I am also going to buy a block tester to see if exhaust fumes are in the coolant to be sure, but if the EGR cooler is leaking, would this also give fumes in the coolant?

It does have an EGR cooler.
If leaking there then I doubt if exhaust woulld leak into Coolant system but Coolant into the gas system.
Scroll down to your Engine EGR System

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Online 2005 Volkswagen Campmob. (Typ2/Transp./LT) spare parts catalogue, Engine group parts, Europe market

www.oemepc.com

 

[Loz]

The loss is so slight you wouldn’t see white smoke so could be a cracked cylinder head or egr cooler. @VW Guru ?

 

[VW Guru]

It is possible that the egr cooler is split it’s easy to bypass the cooler on the old R5 engines take the two hoses off the cooler at the back of the engine and connect the hoses together with a bit of 20mm plastic conduit and retest the system if the coolant doesn’t drop then replace the cooler. It is safe to run with the cooler bypassed on these engines for a short period of time as they are steel not alloy.

 

[Trollhunter]

It is possible that the egr cooler is split it’s easy to bypass the cooler on the old R5 engines take the two hoses off the cooler at the back of the engine and connect the hoses together with a bit of 20mm plastic conduit and retest the system if the coolant doesn’t drop then replace the cooler. It is safe to run with the cooler bypassed on these engines for a short period of time as they are steel not alloy.

Great, thanks for the tip. I think I will have to try that!
I also thought about taking the large exhaust hose off the side of the EGR valve as I see it is an easy clip off to take a look inside. I see from bit of scrolling that if there is a lot of dampness in the soot on the valve this could also be a sign of the coolant moisture as it should be dry.
Tested with a block tester today and showed no exhaust in the coolant.

 

[Trollhunter]

It is possible that the egr cooler is split it’s easy to bypass the cooler on the old R5 engines take the two hoses off the cooler at the back of the engine and connect the hoses together with a bit of 20mm plastic conduit and retest the system if the coolant doesn’t drop then replace the cooler. It is safe to run with the cooler bypassed on these engines for a short period of time as they are steel not alloy.

Should I drain some coolant before taking these lines off?