diesel overheat

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

gfromleeds

Well-Known Member
Posts
2,234
Location
leeds. westyorkshire, uk
Just been on a run and she tryed to overheat!
Strainge thing is the water pipes swelled to hard but werent espesaly hot?
I took the rad cap off and water ****ed everywere but even thought there was lots of steam the water wasent too hot (it was hot but i could easyly hold my hand through the gushing water
Am i looking at the norm (headgasket) or could this be the waterpump?
 
Think you may have a problem. Coolant should not pressure like that if it is not pretty hot. Would hazard a guess it's being pressured by combustion gas. Either that or it was hotter than you think and either water pump is duff or thermostat has failed. You have a little checking to do.
 
I was thinking poss water pump
If its not pumping round would it just sit in the engine and boil?
I pulled the small pipe off thats on top of the rad and loads of steam came out at high pressure pretty sure it was steam not exhaust gas as it had no smell
 
I was thinking poss water pump
If its not pumping round would it just sit in the engine and boil?
I pulled the small pipe off thats on top of the rad and loads of steam came out at high pressure pretty sure it was steam not exhaust gas as it had no smell

Before the thermostat opens coolant is circulated through the head and block via the heater matrix. When the thermostat opens the bypass closes and it goes through the rad. Worth whipping the pump out to take a look. With the pump duff it would as you say just sit there and get pretty warm in a local area.
 
Before the thermostat opens coolant is circulated through the head and block via the heater matrix. When the thermostat opens the bypass closes and it goes through the rad. Worth whipping the pump out to take a look. With the pump duff it would as you say just sit there and get pretty warm in a local area.

Would that produce steam in the rad at pressure but with mildly hot water?
I've not looked yet but is it a big job to get the pump off?
 
Last edited:
Would that produce steam in the rad at pressure but with mildly walk water

Don't forget that water boils at a lower temperature at lower pressure. So the fact that you get steam when you open the system doesn't mean that it was steam when the system was sealed. You opening the cap or releasing a pipe and dropping the pressure can cause the steam. You might do well to get an infra-red thermometer and see what temperatures you have where with the system sealed.
 
As I said on one of your other posts, water pump, RAD, stat & viscous fan are the things to check. HGF does not seem as common as head failure after an overheat. A cracked head will often only show when the engine is called to work a bit harder than normal.
 
Just been on a run and she tryed to overheat!
Strainge thing is the water pipes swelled to hard but werent espesaly hot?
I took the rad cap off and water ****ed everywere but even thought there was lots of steam the water wasent too hot (it was hot but i could easyly hold my hand through the gushing water
Am i looking at the norm (headgasket) or could this be the waterpump?

As I said on one of your other posts, water pump, RAD, stat & viscous fan are the things to check. HGF does not seem as common as head failure after an overheat. A cracked head will often only show when the engine is called to work a bit harder than normal.

A mate of mine said he can do a sniff test at weekend for me
If it shows it leaking exhaust gas is it more likley to need a new head?
 
Worst case we do find gasses in the water
How do you tell if its head or gasket?
Only asking cos at dinner i sat with cap off running and every now and then small bubbles rose up
So starting to think it might have gone but did it overheat because of the leak or is the leak because of the overheat
Feels abit like the Chicken or the egg senario
 
Worst case we do find gasses in the water
How do you tell if its head or gasket?
Only asking cos at dinner i sat with cap off running and every now and then small bubbles rose up
So starting to think it might have gone but did it overheat because of the leak or is the leak because of the overheat
Feels abit like the Chicken or the egg senario

Not really your assuming do all the checks that are free to start with as datatek has said if all work out fine then you go on to the higher step hgf first check the Obvious!!
 
The car seems to drive fine but im only running it 10miles at a time
Gona pull it to bits and weekend and check it over propperly
Like i say had a look at it at dinner
Wheres is the thermostat?
 
Worst case we do find gasses in the water
How do you tell if its head or gasket?
Only asking cos at dinner i sat with cap off running and every now and then small bubbles rose up
So starting to think it might have gone but did it overheat because of the leak or is the leak because of the overheat
Feels abit like the Chicken or the egg senario

Usually heads will not crack spontaneously it is the initial over heating that causes the head to crack. From then on it is the cracked head that causes overheating if everything else is ok. Because it over pressures the system causing water loss and over heat. Best thing you can do if you get a positive sniff reading is to take the head off and check the gasket, any blow will be obvious. If sniff is clear check the water pump, stat and system in general. Stick a static tester on the system check for rapid pressure build.
 
just something else to check while you've the spanners out and your hands dirty, is that the stat is sat in the correct position, I don't think you can fit it the wrong way round in a P38 but you can forget to line up the bypass valve

also when replacing the water pump find one with a metal impellor and not the plastic one that is fitted as standard


WaterPump_zps929848e0.jpg
 
Back
Top