Sprinter Losing coolant

[Bill312D]

I noticed after doing a long motorway run after a while of not doingthem that the van got fairly hot at motorway speeds (80-90) by hot i mean at times getting near the next mark up from 80 (typical running temp) on the guage. after stopping and lettingthe van cool down i checked the coolant level and ntoiced it was wellunder the max so i topped itup and the van ran fine and stuck close to 80 all the time for a few days and a few hundred miles when it started to get a bit warm again,some coolant had disappeared again it oppe dit up and everything was normal, again coolant has disappeard after a few days, any dieas what this could be, now hite stuff inthe oil cap area coolant looks fairly normal it has never over heated in the time I have owned it i have ahad a brief look aroudnf or leaks inthe pipes but i can;t see any is there ac hance it could be a slight head gasket leak or do i just need to look harder at the rad and other joints in coolant pipes? I havn't checked the water pump yet, it was changed about 6 months ago, could some of th ebolts onthis come loose and sprung a small leak? I am guessing as its leaking so slowly it is gonna be very veyr hard to detect, any tips on mkaing it easier?

Thanks, Bill

 

[DGSR777]

Mine did something similar! It seemed to be very intermittent. I changed the rad cap - maybe losing pressure? This seemed to cure it and problem disappeared. However, did notice some water drips on passenger side so maybe heater leaking? Now reluctantly sold but cracking van!!

 

[Bill312D]

the tank onthe header tank seems pretty tight, are you suggesting it could be losing the coolant as steam? hard to check the heater matrix it all still works i'll have a look.

I forgot to mention itnhe first post its a '98 Sprinter 312D (the 2.9 Turbo)

 

[DGSR777]

Mine was a '96 213. The system is pressurised so any leaks are not good. Any excess coolant blows through the overflow tube where the cap sits. I'm no expert but a new cap is pretty cheap. I always bought from Mercedes direct as they are more than reasonable! (quite often non original parts fetch far more than genuine on ebay!!)

 

[Bill312D]

right i'll give it a try then, anyone got any other ideas, as i'd liek this to fix it but i think it could be something more...Like i always do haha

 

[Bill312D]

Just thought I would conclude this topic for anyone looking through later on. I bought a new cap for the header tank,the sprinig was noticabley stiffer than the old one, topped up coolant fitted it and everything is good again, will cruise along at80-90 with the needle bearly lifting off 80 degrees.

 

[Bolide]

Probably the cheapest fix for coolant loss ever... Good call by DGSR777

Nick Froome
www.w124.co.uk

 

[Bill312D]

got to drag this back up. Been having some problems with various fuel fitlers recently, so the van ha sonly been doing 65 max, i let some collant out opening the header tank when the engine was hot (don;t ask). but it dind;t seem to miss it due to the low speeds, however is orted it this week and upon going over 70 for long periods of time again and climbinghills more rapidly the temp has been gogina bit mad heading up towards 90 pretty quick at times, i topped up the collant and it has only aided the problem a little, i guess this is air trapped in the sytem somewhere, whats the best way to get it out? or a different reason?

Thanks again

 

[cobe]

bill 312D

hi Bill, only top up the water when she is stone cold,I start my sons cold, take off the cap,fill to max mark,then make sure cap is on good and tight! and although you proberly have,make sure the rubber sealing ring is still in the cap,Mike.

 

[IAN MAC]

Try running at a fast idle with the cap off Bill, just let any air escape to atmosphere.
Though it still sounds like you need the head gasket done...

 

[Jacko918]

Hi Bill, Jacko here.

I take it yours is the old "Gear lever poking out the floor" type. We had alot of these (5 Cylinders) on our fleet and to be honest I think they were a lot strong and more reliable than the later CDI model. They went pretty well too.

However, one of the things we found they were prone too was a head gasket, we didn't have loads go but we had our fair share. They would leak at the back of the engine on the drivers side. If it's just losing coolant, providing you keep an eye on it and it's not excessive, it's not a problem. But if it starts to run hot, possibly due to the cooling system pressurising due to cylinder gas leaking into the system then it could possibly start overheating.

Best way to check is to get it pressure tested by a garage and look at the head gasket line particularly at the back. Most pressure tester now have a dye that you can put in them to detect combustion gases in the cooling system that will also help you diagnose if the gasket is faulty or not. Also if you run the engine with the pressure tester on and pressurised for a short while the needle should stay roughly were it is, if it starts to climb and doesn't stop it could also mean it's pressurising.(assuming you haven't overfilled the level.)

If you do have the head gasket done then get the head checked for warping and cracking as we had a few fail on this also.

 

[Bill312D]

thanks for that, how much should i be looking to pay for this sort of testing?

 

[Jacko918]

I presume you mean for the pressure testing with the dye? I would say no more than about half hour labour (whatever the garage you uses hourly rate is). Obviously I'd use an indie rather than a dealer..........

 

[Bill312D]

wouldn;t ave to be amerc indie though would it, anyone could do it right? proiding they have the kit for it

 

[Bill312D]

Just thought i would add that there is a hos wein hose heat exchanger in my coolant system for heating the vegetable oil, it is plumbe din paralel with the heater matrix. when i tuyrn the heater to cold which stops the flow of coolant through the heater matrix temperature stays relativey stable however when it is turned to hot the problems persist.

 

[Jacko918]

No it doesn't have to be a Merc indie, just anyone who has the kit and most garages would have it as it's no more than about £150 for the kit.

Not sure why the problem is worsen when the heater is turned to hot. I can only guess that the water takes a "short cut" through the matrix when it's on and doesn't lose as much heat as when it goes through your veg oil heater. I think that's more masking the symptom rather than actually curing it.

 

[Bill312D]

did a run today, kept the heater on cold mos tof the way (until ig ot too cold thenhad it on hot for a bit) and it maintained a good temp (80c ish) the whoel tiem eevn doing 75 up Reigate hill, onthe M25 and crusing at 80-90 the rest of the time, when allowed to coola fter the journey there wasa fair bit of space inthe header tank for more coolant...I'm thinking there was a real stubborn air lock in the heat exchanger which i have got rid of in part by forcing the flow through it by turning the heater to cold

 

[Jacko918]

Try this, Top your coolant up to the Max mark and no more.

Find the rad overflow hose, it's a small flimsy black hose on the front of the rad near the rad cap. Then get a small coke bottle and drill a hole in the lid and push the free end of the overflow hose in to the lid and attach the bottle to the van.

Now drive as normal, providing you haven't over filled it in the first place, any coolant shown in the bottle after a run will show that it's possibly pressurising and forcing it out of the overflow, hence why you have coolant loss but no external leaks. This could simply be a weak rad cap or, as I suspect, it's pressurising.........

 

[Bill312D]

I was considering that, it is getting nearer and nearer to the correct ambient temp though as i keep topping up and running the water through the HX, i will try this anyway though, but if it is pushing some out then it'll be the gasket as i replaced th rad cap when i first got the problem that made me start this thread and it knocked it on the head...unless its a duff one.

 

[Brian Warnock]

Ihave been searching different forums for someone with this exact problem. I have owned a 51 plate 208 cdi for 4 years without any problems. Two months ago I started losing water. Couldnt find a leak but noticed my front nearside tyre was always wet. It transpires that the expansion tank was blowing coolant out the pipe that exits in the wheelarch. The local garage diagnosed blown gasket and replaced that along with the thermostat. I have also put anew radiator cap on.Problem has returned but to a much lesser degree ( approx 70 miles to a half pint of water).I know this because I cable tied a 2ltr water bottle to the inner wing and dropped the hose into it. Mechanic is scratching his head and blaming some other unknown problem. Can anybody advise? thanks, Brian Warnock