John Deere 8R experts needed, coolant pressure problem ?

[SteveO]

Hi,

I have a problem with JD 8360R, it got 1,25 Bar pressure in the expansion bowl and it blowed cooland out.
We thought it was head gasket and we replaced it, machines the head, new bolts and all and today same f..king thing !

What could push the pressure in cooling system ? Head was checked and it looks good, no cracks or anything.
No water in oil and no oil in water.

Where does the cooling system meet pressure so it can boost in the system ?

Thanks a lot

 

[Phil P]

Does it build pressure at idle or only under load?
Possibly egr cooler if only under under load (boost), cracked liner of at idle but usually see coolant in the oil with a cracked liner and cylinder can hydraulic.

 

[SteveO]

No just in the field, at home at full throttle all ok, it can get to 85° max, when it pulls 5m disc harrow and temperature goes to 95° then it blows, after like 10-20 min of work.

DPF and EGR are deleted, DPF pipe replaced and EGR plate installed. Shpuld I unplug EGR then maybe ?
In EGR cooler everything was dry, also no smoke of any kind from the exhaust.

How it can be egr cooler ? Is it plugged on exhaust part (plate is installed) or antifreeze line inside the cooler ?

 

[Phil P]

No just in the field, at home at full throttle all ok, it can get to 85° max, when it pulls 5m disc harrow and temperature goes to 95° then it blows, after like 10-20 min of work.

DPF and EGR are deleted. In EGR cooler was all dry, also no smoke of any kimd from the exhaust.

How it can be egr cooler ? Is it plugged on exhaust part (plate is installed) or antifreeze line inside the cooler ?

Egr cooler has coolant flowing through. Is it blanked off at exhaust and inlet manifold side? Will get pressure from bother sides. Has egr valve been removed?

 

[SteveO]

I think it was blanked with a plate right next to EGR, 4 screws, I think it is before EGR cooler. Coolant part is of course not blanked, cooler is still mounted.
EGR is not removed, I can just unplug the plug from it but it should make no difference if it is blanked ?

Before I changed the gasked blank plate was not installed and I got same problem so it is not blank plate fault.

 

[Phil P]

I think it was blanked with a plate right next to EGR, 4 screws, I think it is before EGR cooler. Coolant part is of course not blanked, cooler is still mounted.
EGR is not removed, I can just unplug the plug from it but it should make no difference if it is blanked ?

Before I changed the gasked blank plate was not installed and I got same problem so it is not blank plate fault.

As long as the cooler is blank both ends it won’t be that. But could be getting some pressure coming back though the egr valve though if not blanked at that end even if it’s not opening. There’s not really anything else other than head and liners after that, don’t think the turbos are water cooled on them?

 

[SteveO]

You mean exaust pressure inside EGR cooler boost coolant pressure ? But then I should have coolant leak in the EGR cooler ? It should be impossible even with 1 blank plate. It cannot pass any pressure even if the EGR is opening.
I dont see how it can be that ?

 

[Timbo]

Egr cooler needs to be blanked both ends- thats to say exhaust manifold end and intake manifold end. Ideally blank coolant lines and remove the cooler itself entirely.

 

[SteveO]

Really ? What is causing this ?

 

[Phil P]

Really ? What is causing this ?

The coolers can split internally then either exhaust or boost pressure is forced into the coolant system. It use to be a really common issue when 30 series first came out.
If egr is deactivated remove the cooler to be sure out of the system or blank BOTH ends.

 

[SteveO]

Thanks a lot man ! Will try that.

 

[SteveO]

Just quick question, I blank exaust canal on both ends on the cooler, not coolant canal ?

 

[principal skinner]

ours had two egr coolers and a head gasket before i saw sense and sent it up the road.

 

[SteveO]

Egr coolers and valves can be deleted, why only JD eats head gaskets like hamburgers, I havent heard about other tractors doing that so often.

 

[Phil P]

Just quick question, I blank exaust canal on both ends on the cooler, not coolant canal ?

Yes blank both ends so no gasses can get into it. You may find it fills up with coolant eventually though if it is split internally.

 

[daveydiesel1]

Is turbo not cooled by coolant? Iirc a 7r series had this but could be wrong? Have a relative who told me his buggered up and ended up way coolant in the cylinder iirc

 

[SteveO]

Just to inform in case anyone will have similar problem.
Today I worked 2 hours and no problem, I have welded EGR cooler and it seems that this was the problem

 

[Phil P]

Just to inform in case anyone will have similar problem.
Today I worked 2 hours and no problem, I have welded EGR cooler and it seems that this was the problem

Hare to say, but, told you so

 

[SteveO]

I should have asked before I spent money on head gasket

 

[Timbo]

I should have asked before I spent money on head gasket

But at least you've overhauled the top end now