Help wanted. Suspected head problems.... But maybe not

[Punderhead]

Hi all.

I have a 95 gq td42 patrol, with a dealer fitted safari turbo.

On a trip to Fraser Island about a month ago, I cracked the radiator, and got the engine quite hot, although I noticed before I fully redlined.

I replaced the radiator, and have been driving it since with no problems, until this weekend.

I had just been driving up a steep hill, so revs were high. 2 minutes later my engine was getting hot so I pulled over. When I had let it cool, I popped the cap and found that I was missing half my coolant. I filled it up again with water, put the cap on and started the engine, only to have the coolant start pumping out the overflow. I pulled the cap off, and ran the engine, and had major bubbles, which were quite frothy also.

Everything so far pointed to a head gasket or cracked head on the gas side. (No water
In the oil or vice versa)

But we then stuck a thingo (don't know the technical term) in the coolant while it was running, and it said there was no exhaust gas in the radiator. We stuck it behind the exhaust, and the tool does work, and didn't appear faulty.

Any other thoughts on these symptoms?

Thanks I. Advance

[nissannewby]

A combustion gas tester don't seem to be reliable in the diagnosis of a head problem in my experience.

Is there bubbles at initial start up when cold?

[Alitis007]

What condition is the radiator cap and thermostat in ???? If you filled up a scortching hot motor with cold water it'll start boiling instantly and if the cap is failing it will allow the water to go past it but if the thermostat is jammed half open it might be restricting the flow.

Did you replace it with a new or secondhand / reco
unit???

[Punderhead]

What condition is the radiator cap and thermostat in ???? If you filled up a scortching hot motor with cold water it'll start boiling instantly and if the cap is failing it will allow the water to go past it but if the thermostat is jammed half open it might be restricting the flow. Did you replace it with a new or secondhand / reco unit???

Cap and thermostat a new. Radiator was replaced with a good condition second hand one.

[Punderhead]

A combustion gas tester don't seem to be reliable in the diagnosis of a head problem in my experience. Is there bubbles at initial start up when cold?

Haven't started it cold to check as I left it at my mates house. I was afraid someone would say that but hoping that there would be some ohther explanation. Will be doing a compression test tomorrow, when my mate can get the gear.

Cheers

[Alitis007]

There might be a small possibility that the second hand radiator is partially blocked. I would first pressure test the cooking system to eliminate leaks, then I would do a test to see if compression is enetering the cooling system ( not so much look for gasses like that other tester)
You can mak a makeshift tester by cutting the bottom off a small plastic bottle ie coke, fanta etc, tape the neck up where the cap screws on to so that it fits tightly inside the radiator neck and fill it with water roughly a quarter of the way. Mark it with a texter to note where the water level is, next disconnect the fuel cut solenoid from the ip so the motor won't start then get a friend to crank the motor while you watch the water level. If it rises you've got a head problem, if it drops then your laughing (sort of lol )

If you don't have a head fault then get your radiators core inspected

[johno1938]

radiators & other parts are so cheap these days with all the competition btween shops
why muckaround with s/h rubbish
chem co testers work if used properly
if b ottom rad hose is cool then theres a blockage ,rad. thermosat
ha air cooled engines dont have this problem ay
get a 20 lt drum stick it on the roof ,run a hose down to your heater hose from bottom ov drum run other heater hose to top ov drum fill with water
use as non pressure system
ran a bulldozer like that 4 years
lmfao

[threedogs]

a 2nd hand radiator sounds suss to me it could just be freshly sprayed black with no testing cause
"it looked ok" get the radiator re-rodded if all else checks out ok

[Punderhead]

a 2nd hand radiator sounds suss to me it could just be freshly sprayed black with no testing cause "it looked ok" get the radiator re-rodded if all else checks out ok

It was out of my mates patrol, he had had no issues with it, he only pulled it out cause he had scored himself an upgraded one for nothing from his dad.