Now it's a coolant problem...

[OZ9HZ]

I am not having good luck with my three 2,0 Hdi Berlingos this week.

One is up on the lift with a bad steering wobble, probably because of a damaged steering rack.

One just got stuck in reverse and the gear lever is flopping around like a dead fish. I hope it's just some linkages that have popped off and need replacing...

The third one has an unpleasant feeling problem... I suspect it may be quite expensive. Here are the symptoms... When I start it it drives ok mostly, but after about 5 or six km the temperature gauge pushes steadily up to just over 90 degrees, then starts to come down again and will sit at about 60 degrees for quite some time. The coolant warning light will blink on, and then will go off (it seems this mostly happens when I slow down, but that could be a coincidence). It seems a bit random, but I am using a lot of water... about 2 liters for a 20km trip, but sometimes it's a lot less... I can't put my finger on the problem. I drove 125km on Saturday without the warning light coming on and without the temperature going above 90, but after I stopped for twenty minutes the warning light was on, and the car took about 3 liters of water.

One thing I have noticed is that there seems to be some pressure build up in the coolant expansion bottle... when I open the top I can hear pressure releasing. To my mind this has always meant a blown head gasket... Am I likely looking at a gasket replacement / head skim? Or is it maybe something less serious like a water pump problem?

I have been thinking that I may have a thermostat that is faulty... shouldn't a thermostat kick in at about 70 degrees? I might have a combination of thermostat and leaking pipe somewhere.

Any ideas? Unfortunately I have to keep using this one at least until the weekend because it's my only one that runs currently.

Marc

[Gadgetman]

You really need a pressure tester.
It's a kit with a pump and gauge, and a whole lot of different radiator caps.
Install the one that fits on your car, connect the pump, and start pumping.
Pump it up to 1.5 Bar or a bit more, and go have a cup of tea.
It SHOULD read the same as before when you return...

If the Head gasket is a goner, you should normally find peanut butter in the water.
And in severe cases, you'll find the radiator cap on the ground...

The radiator cap has a spring-loaded walve in it. It should hold tight for pressure up to 1.4Bar or somewhere around there. If it has failed, weird stuff can happen...
(You have 3 Berlingos? Should be able to borrow one from one of the others, then.. )

[oilyrag]

You really need a pressure tester.  
It's a kit with a pump and gauge, and a whole lot of different radiator caps.
Install the one that fits on your car, connect the pump, and start pumping.
Pump it up to 1.5 Bar or a bit more, and go have a cup of tea.
It SHOULD read the same as before when you return...  

If the Head gasket is a goner, you should normally find peanut butter in the water.
And in severe cases, you'll find the radiator cap on the ground...

The radiator cap has a spring-loaded walve in it. It should hold tight for pressure up to 1.4Bar or somewhere around there. If it has failed, weird stuff can happen...
(You have 3 Berlingos? Should be able to borrow one from one of the others, then.. )

If you are just topping up each time without bleeding the system then there's the risk it will keep sicking up the coolant. There's the possibility that it's no more than an air lock . I'd guess that there are a couple of bleed points - one at the bulkhead where the heater pipes enter, and the other on the thermostat housing and the chance of another at the rad where the top hose enters - depends on model, and someone here can advise?
One way to get rid of a big air lock, along with bleeding, is to cut the bottom out of a 1 litre white spirit container, wrap some foam type tape around the neck and push it into the radiator filler cap neck, making sure it blocks the overflow pipe.  Only top up the rad to the normal level and then let the engine run until the stat opens - you'll feel the top hose warm up. Then raise and drop the engine revs and, if there is an air lock the water will suddenly start to fill the container - support it at this stage - and increase/decrease revs. The air pocket will vent into the bottle and the level will then suddenly drop.  Switch off and top up, ideally with warm water, and do the same again.  Don't overfill the rad and drive to see if things have changed. 
Good luck

[OZ9HZ]

This afternoon I will have a little time to investigate a bit further... unfortunately I don't have a pressure tester, but I will be able to strip the thermostat out of one of the others, and I'll completely drain and then refill the coolant system and hope for the best.

I don't see any milkyness in the oil, and I don't detect any oilyness in the coolant, so I don't think there's an oil/coolant break in the head gasket, but I haven't been able to have a good look to see if coolant is maybe leaking out of the head... Of course, it could be a simple split pipe or cracked coolant bottle... 

Cheers,
Marc

[saskak]

This afternoon I will have a little time to investigate a bit further... unfortunately I don't have a pressure tester, but I will be able to strip the thermostat out of one of the others, and I'll completely drain and then refill the coolant system and hope for the best.

I don't see any milkyness in the oil, and I don't detect any oilyness in the coolant, so I don't think there's an oil/coolant break in the head gasket, but I haven't been able to have a good look to see if coolant is maybe leaking out of the head... Of course, it could be a simple split pipe or cracked coolant bottle... 

Cheers,
Marc

If you are emptying and then filling again, definitely do what oilyrag said, i.e. bleed the system. This if for the 1.6HDi, but you can get the idea: https://www.youtube.com/watch?v=CSmm2SCpPCs  . Because the second (heater matrix) bleeding point is higher than the tank level I used a header tank, same thing oilyrag mentioned.
You are using an enormous amount of coolant and at the end of the day it has to go somewhere. Apart from the milky coolant, check if the oil level is not increasing.

[OZ9HZ]

Feedback:

Thank you to everyone for the advice. I swaped the thermostat with one of my other cars, and made a header tank and bled the system.

The thermostat now kicks in at around 70 degrees, and the car stays cool for a whole 18km trip to town. It looks like it's stopped using much water now as well...

BUT...

If I open the coolant reservoir cap while the engine is running a lot of air bubbles can be seen, and the cooling warning light goes on when I start the car and then goes off after about three or four kms... I guess until the thermostat opens.

I am suspecting there is a small crack in the head gasket that is pushing exhaust gasses into the coolant?

[Mark604]

Better minds than me know of these things, I'm just an old unelectronic mechanic, but wouldn't it be that if exhaust gasses are entering the coolant system, it would over pressurise and either blow something or chuck water out of the overflow?

I'd personally check again it's been bled properly, leave the cap on and and run it for some days and see how it goes rather than making any engine stripping down decisions yet.

[OZ9HZ]

Better minds than me know of these things, I'm just an old unelectronic mechanic, but wouldn't it be that if exhaust gasses are entering the coolant system, it would over pressurise and either blow something or chuck water out of the overflow?

I'd personally check again it's been bled properly, leave the cap on and and run it for some days and see how it goes rather than making any engine stripping down decisions yet.

Yeah, that's what I'm thinking to do... I am concerned that the coolant warning comes on shortly after start up, but the goes out after a few km, and my reasoning is that the reservoir cap has a presure reflief valve, so excess pressure may be leaving through there?

As for stripping the engine... this car just has to work for a few days until I can get one of the other Berlingos running again. I bought this particular one just for the wheels, doors, and a few extra bits that are better than on my other two. It's an organ donor that's just not quite dead yet

[Mark604]

Just curious, does the warning light come on if you've not undone the cap? So like drive it one day, do nothing and the next morning you start up and does the light then come on?
Also, what is the warning light actually warning you of?
Lastly, the pressure relief valve - it's the usual type of cap with a spring and when the pressure overcomes the spring it moves to allow relief out of a pipe? In any case, where does the pressure go? Vent to atmosphere? If so, wouldn't you see water escaping as well and dropping on to the floor?

[OZ9HZ]

The warning light is apparently for high temperature and for low coolant level. Seeing as it goes on when the car is cold, and then switches off, I have to assume it's the low level warning. Why would it light up and then go out later?

I wonder where thge sensor is physically placed in the system? Surely it's on the engine block somewhere and not in the bigger system after the thermostat? Faulty sensor unit?