Merc atego 815 temperature warning lights up and down! Help

UK PROFESSIONAL DRIVERS FORUMS OWNER AND FLEET OPERATORS FORUM (INTERACTIVE)
1

Have a 2003 815 atego and over the last few month ive had a problem where the temperature goes away up to 111oC and above , buzzer sounds but then it goes back down to normal. Then within minutes goes back up and down. Etc etc.

What could this be? Thanks

2

Also, when it (overheats) like this i can only get cold air from the blower? I take it that this is related?

3

Sounds like air lock in sytem, was it drained and refilled before syptoms started?
Dont no your vehicle but there is often a bleeding process to get air out of cooling system.

4

As baz says, probably an airlock.

5

Thanks for the replies. It wasnt drained. I have also noticed a small drip coming from up near the waterpump. Would this small drip cause an airlock? I topped up the coolant with the truck running and notice airbubbles escaping.

If i were to put some k seal into the coolinf system would it sort the drip out?

Thanks

6

Kseal is good but if drip is from pump i suspect pump is on the way out.
Yes loss of fluid could cause air lock.

7

Leak from pump might be causing belt to slip then drying off and going again for a while or it’s just knackered and working intermittently, sounds like a new pump job though if it’s just dripping from the flange and not the pump seal you might just need some hylomar type gasket seal. That would be my preferred fix over the various header tank pour in type products.

8

All of the above is good info, just one thing to remember, it may be just a drip now, but leaks never ever get better, only worse, time to get that sorted before you end up with a tow in and no choice in how much you spend to get it fixed :wink:

9

Hello

I have had this problem with a few mercs, The dripping from near the pump is more than likely the tell tale hole from the pump. It tells you that the pump seals have failed. The reason the heaters go hot and old is due to air locks, or lack of coolant. Suggest new pump and while your at it change the thermostat while its apart.

As a engineer that runs a my own workshop looking after numerous customer vehicles i would never recommend using any temp sealing solution, these are mainly for a breakdown situation and not a permanent fix and will cause long term problems to water ways, pipework etc

alasdair

10

newmercman:
just one thing to remember, it may be just a drip now, but leaks never ever get better, only worse, time to get that sorted before you end up with a tow in and no choice in how much you spend to get it fixed :wink:

Wise words indeed :sunglasses: , once left home for a weeks work one monday morning and by that afternoon noticed the smell of coolant and a drip or two on the floor, by friday afternoon I was pouring 20 litres of tap water an hour into the flaming thing trying to nurse it home :neutral_face: I well remember having to stop on the hard shoulder of windy hill so the old girl could have her final fix of water for the last hours run back home… :slight_smile: