Hi guys looking some help. Have a 2010 R500 that has the coolant level light coming on and off. When i fill it and it heats up it blows water out of the header cap. Also when i switch engine off it gargles for about 15minutes. Is this just air in the system (if so is it easy enough to bleed ) or something more complicated?? And another thing the heater blows cold air no matter how high it is set at…
Im no expert but it sounds like a blown head gasket. Can be checked easily by a mechanic with a CO2 testing kit.
I stand to be corrected on this as I’m not a mechanic, Scania’s don’t really suffer from head gasket failure as they use individual heads with sealing rings of some description ( was told this by a scania fitter ) so unless you have a cracked head on one of the eight pots then it’s most likely air in the system, I had a similar problem on my V8 with the gurgling and cold heater you mention, it turned out to be a cracked plastic ( not rubber ) pipe which ran from the header tank along the n/s ( on a rhd ) of the heads and around to the other side, if you just want to try bleeding it first then I was told two different ways by two different Scania fitters, one is to top up the header tank and gently pressurise the system with an air line with cloth wrapped around to stop the air coming out, this allegedly forces the trapped air out of the overflow, be careful not to put to much pressure in though, the other way ( which I used ) is to fill the header tank run the engine warm and gently remove the pipe that runs from the bottom of the square box that sits alongside the header tank until the bubbles disappear, that square box is the electronic control box for the heater which may be at fault for the cold heater as they either stick open or closed when faulty, hope this helps.
Fit a hose pipe on the bottom of the radiator you need a certain fitting for it, then remove 1 of the hoses off the bottom of the header tank and bottom fill it, you should hear all the air release then let it over flow for a while before fitting pipe back on the let header tank fill up too
I don’t have experience of the V engines, however the inline 4 series I worked on had a connection at the rear n/s of the block which required a special fitting to be attached to fill up the system when it had been (partially) drained. Again on the inline engines, the water pump impeller had a habit of shearing off which leads to symptoms similar to those described because the coolant is not circulating.
Seen similar before remove radiator and jet wash behind it you will be suprised how much rubbish gathers in between rad and engine?
Thanks for your replies lads will try a few of your suggestions today 
hanson:
Seen similar before remove radiator and jet wash behind it you will be suprised how much rubbish gathers in between rad and engine?
I would certainly agree that the rad does accumulate lots of muck inside and out and especially on vehicles which go off road. This of course leads to the same symptoms. Oh the joys of getting a 4 series rad in and out! Although I’m sure loads will disagree with me I reckon that the 3 series was just so much a better vehicle.
Is it also losing air?
I drive an r420 and last week I had exactly the same problem. It got worse and worse over the week until I was stopping every 45 mins to refill the water and they had to get me straight back to the yard. The problem was a blown gasket on the air compressor
Also buy a new cap for the header as the seal on the old one has most likely fallen put and got lost
We had a 2007 R580 in our yard suffering from over heating and boiling it turned out to be the compressor was knackered and was pressuring the coolant system. Head gasket failure is rare on the 8 pot engines as far as i know.
If it had a cracked pipe or blocked rad, you wouldn’t get the coolant being blown out of the cap as soon as the engine gets warm.
You would either just loose coolant in the case of a cracked pipe or overheat then perhaps loose coolant via the rad cap in the case of a blocked radiator.
Your cooling system is getting pressurised. So this points to HG failure or as others say via some kind fault in he compressor. All I’d say though is just because Scanias apparently rarly suffer from HG failure doesn’t mean one never will.
Just one more though. Is the coolant water based ? It could just be a radiator cap failure allowing the coolant to boil prematurely.
I had to have Scania assistance out to me today in Stockton on Tees. Driving along and heard a loud noise and immediately a red warning came up on the dash(13 plate p310 rigid), ALTERNATOR NOT CHARGING followed not long after with ENGINE MALFUNCTION and COOLANT TEMPERATURE TOO HIGH . Thought the belt had come off.
When the Scania lad turned up,he jacked the cab up and found that the pulley had sheared off! He had another new part in his van so it wasn’t a problem. The belt was fine!!
Apparently,this happens a lot and he reckons Scania are looking into it. The truck has done 270,000 kms.
Aye harry monk shes losing air…
Harry Monk:
Is it also losing air?
Yes mate. 9 hours of and she be down around 10bar!
Secretelephant:
If it had a cracked pipe or blocked rad, you wouldn’t get the coolant being blown out of the cap as soon as the engine gets warm.
You would either just loose coolant in the case of a cracked pipe or overheat then perhaps loose coolant via the rad cap in the case of a blocked radiator.Your cooling system is getting pressurised. So this points to HG failure or as others say via some kind fault in he compressor. All I’d say though is just because Scanias apparently rarly suffer from HG failure doesn’t mean one never will.
Just one more though. Is the coolant water based ? It could just be a radiator cap failure allowing the coolant to boil prematurely.
begining to think head gasket myself mate. With heater blowing cold and it still pressurising.
What do you mean is coolant water based?
Sounds like a compressor head gasket, but scania’s do need bleeding, the easiest way is to pull the small pipe off the front of the heater control valve, take a deep breath, and blow with as much pressure as you can down it, make sure you remove the header tank cap first, you should hear gurgling coming from the header tank, as the water drops down into the system, you should, after a few blows, get water coming out of the pipe you are blowing down, job done. 
magnetman:
Aye harry monk shes losing air…
It’s the compressor head gasket then.
jimmy2loads:
Sounds like a compressor head gasket
This.