The TGA I normally drive (2003 26.410)has a problem where it’s losing a substantial amount of coolant - 4-5l every 100 miles or so! It’s been in and out of the dealership several times, and comes back each time with them saying ‘We don’t know, it could be x, or y, or z’. There’s no sign of contamination in the oil, and no sign of any puddling underneath. It had a new engine in it 18 months ago - the lorry has done just under 1m ks, and the new engine about 150000ks.
Does anybody have any experience of any possible places to look? The engine seems to run as good as it ever did, and there’s no sign of any smoke of any colour from the exhaust, so where it’s going is a mystery.
The boss is talking about buying a new unit to replace it, but in the meantime it would be good to get it sorted (if it’s not drastically expensive) - particularly as it’s a manual and any replacement would probably be an auto
take the cap off the header tank fill it with water and start the engine,if it blows out the water then either the head gasket is gone or if the comperessor is water cooled the gasket in the compessor head could have failed letting air into the system resulting in the header tank getting pressurised with air and blowing the water out through the overflow.
scotstrucker:
take the cap off the header tank fill it with water and start the engine,if it blows out the water then either the head gasket is gone or if the comperessor is water cooled the gasket in the compessor head could have failed letting air into the system resulting in the header tank getting pressurised with air and blowing the water out through the overflow.
The compressor bit could make a lot of sense - it’s been dropping air overnight ( in the last few days has been dropping to zero). Sounds like the compressor could do with a bit of investigation. Thanks for the tip - I’ll make that the next thing to check.
I did wonder about that - very occasionally there is a faint whiff of hot dampness in the cab, but wouldn’t there be water or condensation somewhere inside with that?
If the air tanks have a train try them see if any water comes out?
Could tilt the cab and check if the compresser head gets so hot you can’t touch it! It shouldn’t I’d so Thers the issue! Seen it on a few scanias
scotlanddriver:
Check the air tanks for the coolant, I had damaged (cracked) the compressor’s head and the coolant was going in to the air brake system.
I’ll give that a try - it would at least explain where it’s all going!
drain air out of tanks, build up air pressure but turn off engine before the air drier blows off, turn the engine off the remove the rad cap. if the compressor head gasket has gone there will be air bubbles in the rad water .
i had a 2003 tga 410 a few years ago and that was using loads of water. i checked various things and i noticed the oil level was to high. i removed the sump, pressurised the cooling system to find the water was leaking down the inside of the front timing chest into the sump
another possibility which even man men forget is the egr cooler, so your water leak is going out via the exhaust/silencer
Had a cracked compressor head on an Actros doing similar, but with not quite that sort of coolant consumption
The givaway on that was when the air pressure reached its working level and the compressor blew off, a puff of steam came out of the exhaust at the same time Turns out the compressor is water cooled and the regulators exhaust pipe is plumbed into the engine exhaust silencer, MAN’s probably use the same cost/noise/weight cutting ideas.
A new comp head fitted, the steam disappeared and coolant level remained stable
It all seems that the compressor is no1 place to start! One other thing I’ve just thought of - the remaining coolant never seems excessively hot, going on previous car experience if a head gasket goes affecting the waterways, it tends to boil the water that’s left (think that’s right, been a while!). Also, the header tank has quite a bit of pressure in it even when it’s sat for a weekend and everything is cold, again pointing towards compressed air & water meeting somewhere.
Thanks for all the help folks, I’ll have a dig around this weekend and hopefully be able to buy you all a virtual pint next Monday!
if you go down the compressor head gasket route. if you buy a gasket set from man you will see in the set a small “O” ring
when removing your head look at the old gasket because some are fitted with a loose o ring and some are fitted without the loose o ring in the head gasket.
approx the diameter of a pencil
It’s all looking very promising then - certainly enough to spend some time pulling it apart and checking it out! Does anybody know the torque wrench settings to put it all back together - I presume it’s going to be similar to a cylinder head for refitting?
I suppose if it hasn’t got EGR, that’ll narrow the field down considerably further!
Turns out the compressor is water cooled and the regulators exhaust pipe is plumbed into the engine exhaust silencer, MAN’s probably use the same cost/noise/weight cutting ideas.
