Coolant issue

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Syncronorth
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Coolant issue

Post by Syncronorth »

Just got a second hand DJ engine without any history replacing my old that didn't run.

After bleeding the coolant I drove it for around 40 miles where the needle indicated the engine running a bit hot, but with the front and rear heater on it was indicating normal temperature.

Next day the red coolant light in the dash started blinking after a 5 min drive. The expansion tank where almost emty, unscrew the blue cap and water came fizzing out. Let it rest for some time then drove back home without any problems.

Next day I made sure the expansion tank was full before starting, but only after two minutes the red light in the dash started to blink, same issue with coolant missing from the expansion tank and when unscrewing colant came from nowhere and it was running over.

Removed the temorstat (didn't bleed the system afterwards) at first it seemed that everything was fine, but after about 10 miles red light came up again, and I had same symptoms as before.

Don't know too much about engines but I'm thinking this is exhaust entering the coolant, what do you guys think?

Should I do more tests? New thermostat? Swap the blue cap? Bleed again? Any help are much appreciated
1983 camper 1.9 DG 1985 transporter syncro 1.9 DG and one 1985 8-seater syncro 2. 1 DJ

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Aidan
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Re: Coolant issue

Post by Aidan »

At first reading it sounds like you need to properly bleed/fill the system and I'd recommend you put the tstat back in if it's known working one or maybe put a fresh one in if it's not
So heater switched on and expansion tank full, cap on, start the engine then remove the cap and keep adding coolant whilst it comes up towards temperature, don't rev it hard it will surge the coolant and it will spill over but a little revs now and again may see the level drop and you can add a bit more each time till it's stable and approaching hot then pop the cap on and connect the darlek nozzle outlet to the expansion tank and check the level in that is to the full mark, then you can open the bleed screw on the radiator, ideally have a friend put a few revs on it until coolant is coming out freely from the radiator bleed screw then close that off. Check the temp and it should be approaching half way mark on the gauge, the radiator will be getting warm, and hopefully thermostat open, check the coolant return hose is warm and level in the expansion tank isn't too low. If needs be stop the engine, wait a little to let the coolant temp drop then remove cap carefully and add more coolant as necessary, cap on, restart and then take it for a short drive ideally with a little up and down and then check the levels. If there's a product of combustion issue then you should see steam and water blowing out of the top up tank and maybe the flashing light, but if its okay then leave the engine to cool down, if it needs coolant it should help itself to more from the top up tank so when it's cool check the level in that and top up as necessary. The heater should have been working fine during the first test drive, if it is you can switch it off and then go for a longer test run. Top up when cool as necessary, should only need to add to the top up tank if there's no leaks in the system and it is holding pressure. IF the level in the top up tank goes up majorly when driven and it's letting out water and steam from the top up tank then coolant is either boiling (cap not holding pressure) or there's products of combustion entering the water system (cracked head or cylinder sealing issue)
Good luck

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Syncronorth
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Re: Coolant issue

Post by Syncronorth »

Thank you for your reply. Will try a new thermostat then bleed the system properly.
1983 camper 1.9 DG 1985 transporter syncro 1.9 DG and one 1985 8-seater syncro 2. 1 DJ

phinw
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Re: Coolant issue

Post by phinw »

It would be worth getting a new dalek cap anyway. They are cheap to replace and worth keeping as a spare. Get the good quality ones from brickwerks
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Ciaraneng
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Re: Coolant issue

Post by Ciaraneng »

Once you replace the cap and the thermostat and bleed the system, I'd recommend taking it up to running temperature and check for leaks. The pressure builds to about 0.5-1 bar when hot so it might be causing a leak at high temps.
1983 High Top 1.9 Petrol Early DG Engine

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Syncronorth
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Re: Coolant issue

Post by Syncronorth »

New cap and thermostat! Had difficulty getting heat from the front heater during bleeding, water hose going to the front heater matrix is warm all the way after the valve but the return hose is cold at the same moment the rear heater is warm. Continued on bleeding anyway and as soon as I went for a test drive the heat from the front stared to work.

Got back from test drive and refilled the expansion tank and keept on bleeding it. Heat in the front was there for the most of the time but not always.

Second test drive, heat in the front worked intermittently, needle was quite stable. After about 15 min drive the red led started to blink, stopped and the expansion tank was nearly empty while the overflow tank had water higher then the screw cap. Carefully unscrew expansion tank cap and water came raising up filling the tank, drove back without any waring light, but when I was back the water was nearly as low as the hose going to the water pump.

Didn't have time to investigate any further.. Can a small leak anywhere cause this? Can it be the water pump not being strong enough to bleed the system? Blocked front heater? Thinking about doing a new test by bypassing the front and rear heater is there any reason this is a bad idea?
1983 camper 1.9 DG 1985 transporter syncro 1.9 DG and one 1985 8-seater syncro 2. 1 DJ

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Ciaraneng
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Re: Coolant issue

Post by Ciaraneng »

Roughly how much coolant have you added to the system in the past week? Air locks and losses on thermostat replacement etc only account for the corresponding coolant addition. Once the system is fully bled, your level should not be dropping. If you are continually adding litres despite bleeding, it sounds as if you have a leak you need to find and fix. Are you seeing any coolant on the ground when you stop? When the red light comes on can you get under the van and see if there are any leaks?
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937carrera
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Re: Coolant issue

Post by 937carrera »

Aidan wrote: if there's no leaks in the system and it is holding pressure. IF the level in the top up tank goes up majorly when driven and it's letting out water and steam from the top up tank then coolant is either boiling (cap not holding pressure) or there's products of combustion entering the water system (cracked head or cylinder sealing issue)
Good luck

Sorry to say, but I think this is where you are. Are there any signs of leakage from the top up tank / header tank, steam from the exhaust or coolant marks on the cylinder heads ?

It''s probably time to have a sniff test done on the coolant
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Re: Coolant issue

Post by Ciaraneng »

937carrera wrote: Sorry to say, but I think this is where you are. Are there any signs of leakage from the top up tank / header tank, steam from the exhaust or coolant marks on the cylinder heads ?
I would tend to agree as this matched my symptoms. When I had a cylinder head leak, combustion gasses were flowing into the coolant and the pressure rise was lifting the cap on the header tank. As it happened quickly and was gone, I detected it by having my missus drive and I sat in the back with the hatch open so I could see the engine - don't try this if there is any sign of exhaust gasses.

As sniff tests can be expensive and unreliable, another (and quicker) way to test may be to put a rag or a tray under the header tank and the top-up tank and go for a drive until the light goes on. If the rags are dry, the problem probably lies with a leak elsewhere, which is better news than a damaged head. You will also need to examine the heads all round for signs of a coolant leak. Are you using the right concentration of coolant or are you topping up with water? If using water be very careful as (a) it is not as effective a coolant so will cause the temperature to go higher (b) it causes head stud corrosion and (c) it makes leaks harder to detect.
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Re: Coolant issue

Post by 300CE »

If bleeding has been done correctly, it could possibly point to failed fire rings and the system is overpressurising - if you leave it for a day or two to cool right down, open the header tank cap and see if there is a whooshing sound and the coolant starts to come back into the header tank.

Here's a link to the issues i had - does this mirror your problem?:

https://forum.club8090.co.uk/viewtopic. ... 7&t=156646" onclick="window.open(this.href);return false;

If so, it's a probable rebuild job - i have now completed this and she's been faultless ever since.
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Re: Coolant issue

Post by Syncronorth »

Ciaraneng wrote:
937carrera wrote: Sorry to say, but I think this is where you are. Are there any signs of leakage from the top up tank / header tank, steam from the exhaust or coolant marks on the cylinder heads ?
I would tend to agree as this matched my symptoms. When I had a cylinder head leak, combustion gasses were flowing into the coolant and the pressure rise was lifting the cap on the header tank. As it happened quickly and was gone, I detected it by having my missus drive and I sat in the back with the hatch open so I could see the engine - don't try this if there is any sign of exhaust gasses.

As sniff tests can be expensive and unreliable, another (and quicker) way to test may be to put a rag or a tray under the header tank and the top-up tank and go for a drive until the light goes on. If the rags are dry, the problem probably lies with a leak elsewhere, which is better news than a damaged head. You will also need to examine the heads all round for signs of a coolant leak. Are you using the right concentration of coolant or are you topping up with water? If using water be very careful as (a) it is not as effective a coolant so will cause the temperature to go higher (b) it causes head stud corrosion and (c) it makes leaks harder to detect.

Exhaust looks normal and I can't see any signs off leaks. Good advice will test on Monday. Started off with 40/60 mix but probably have much more water then coolant at the moment. Going to messure it, but using something around 20/80 should be okey for testing?


300CE wrote:If bleeding has been done correctly, it could possibly point to failed fire rings and the system is overpressurising - if you leave it for a day or two to cool right down, open the header tank cap and see if there is a whooshing sound and the coolant starts to come back into the header tank.

Here's a link to the issues i had - does this mirror your problem?:

https://forum.club8090.co.uk/viewtopic. ... 7&t=156646" onclick="window.open(this.href);return false;

If so, it's a probable rebuild job - i have now completed this and she's been faultless ever since.

Sounds very similar to my problems except from my front heater not working perfectly. Will do more test on Monday, but preparing mentally for the worst! Did you need to change cylinder heads or just gaskets?
1983 camper 1.9 DG 1985 transporter syncro 1.9 DG and one 1985 8-seater syncro 2. 1 DJ

Sir Brixalot
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Re: Coolant issue

Post by Sir Brixalot »

Is the header tank with the dalek cap drawing coolant from the top up tank?
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Syncronorth
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Re: Coolant issue

Post by Syncronorth »

Sir Brixalot wrote:Is the header tank with the dalek cap drawing coolant from the top up tank?

I'm quite sure it's not drawing anything back just the other way around. Waited 20 min after last drive without seeing any signs off coolant going back, don't know how much time this normally takes?
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Re: Coolant issue

Post by Sir Brixalot »

These vans can be very temperamental if not thoroughly bled then checked for bubbles in the header tank. Takes a while mate to cool down. The reason I ask is that on mine when the cylinder heads seals went, the header tank would still draw from the top up tank. When I have leaks it and the sealed system is broken the header tank doesn't draw from the top-up which gets overfull. Hopefully, it's a leak. Get a bright torch and check all your pipes for crusted pink substance which builds up where the coolant leaks. Start round the thermostat/coolant temp switch area and adjacent to spring clips/hose clamps etc. Is the radiator getting hot all over and not partially blocked? Rule out the cheap and easy fixes first.
Last edited by Sir Brixalot on 02 Aug 2019, 08:14, edited 1 time in total.
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Re: Coolant issue

Post by Pinkythelabrat »

If you take a washable marker pen and draw on the paper/rags you wrap round any suspected areas of leakage it will show if it has leaked and then dried - the pen runs. Handy for hot leaks.


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