Heating issue 4.8

[Craig Lord]

Ok guys I am now stumped...
After missing our whole 3 week holiday around bots I have now replaced the viscous fan, the thermostat and the radiator cap all done by nissan and still the problem persists.

I asked for the new viscous but they also tested the thermostat and said it wasnt opening and that was causing the system to pressurize. They also said that the radiator cap that I got with the new radiator was not the correct rating. So now it's not building that extreme pressure but it's still getting hot...

The symptoms are as follows:

Fine when outside temps are 25 and below. No issues at all at any speed.

After outside temps reach 30 and above it starts.

At speeds above 110 the temp suddenly goes up very quickly to 3/4 and as soon as I back off the throttle it comes back down allmost immediately....

If I drive below 100km it's ok.

All this started after I had the old orriginal radiator replaced in April. Before that I never had any issues at any outside temps loaded or unloaded and I've had the front bull bar on since I've owned the car with no issues so I dont think that's blocking air to the radiator because I never had problems before... BUT.... if I open the bonnet to the second latch and secure it so It cant fly open it seems to help with the problem.

Nissan are staring to use words like head gasket and a crack in the block but before I start to panic I want to exhaust all other possibilities...

So if possible can some kind person with a 4.8 still with an original nissan radiator please measure it and give me the dimensions. I wonder if the replacement one I have is too small??? They replaced the whole thing even the tanks. Not sure how to measure the volume of the tanks but the core will be a good start.

I am also going to take off every single pipe and check for blockages...

If the radiator is fine and the pipes aren't blocked then the only other thing is the water pump. And that seems fine because when nissan replaced the thermostat they also replaced my coolant with new coolant and had to bleed the system. Surely they would have noticed if it wasnt ok?

The frustration is now proper....

[DanieG]

Was the cooling system properly bled after the coolant was filled? I had the same worry after I had to replace the coolant. It took several times of bleeding at two places before the problem was solved.
Maybe this is the problem, I hope.

[Craig Lord]

Ok just been back to Silverton where they did a chemical test for exhaust gasses in my coolant and the head gasket is leaking.... dont know when or how because I have never cooked the car since I've had it so I must just have really bad luck.

Merry Christmas to me

[Craig Lord]

Ok just been back to Silverton where they did a chemical test for exhaust gasses in my coolant and the head gasket is leaking.... dont know when or how because I have never cooked the car since I've had it so I must just have really bad luck.

Merry Christmas to me

Addition: quote from nissan for head gasket replacement and skimming the head as near as makes no difference P24000.00

Total parts: P9000
Total labour: 12000
VAT: P3000
Thats only if there is no other more serious damage. Once you go down the rabbit hole of taking off the head I'm worried about what else they might find ...

[Tinus lotz]

Dude what radiator have you got there?

[Craig Lord]

Dude what radiator have you got there?

Went back to silverton they said they have to order another one for comparison because they dont keep them in stock... either way there is still blow by into the coolant according to thier tests. Nissan will have to do a compression test to confirm.

Current radiator is 58cm wide x 3cm think x 64cm high

[Tinus lotz]

Spoke to frans when we had the club 23 drags ...the pirate 4.8 has like 12 pipes less than the nissan one ...please dont trust silverton checks lots of people have removed heads for no reson what so ever .....if you water is getting less yes if not .....dont think so

[Craig Lord]

Spoke to frans when we had the club 23 drags ...the pirate 4.8 has like 12 pipes less than the nissan one ...please dont trust silverton checks lots of people have removed heads for no reson what so ever .....if you water is getting less yes if not .....dont think so

I also called nissan Botswana to ask about genuine nissan radiators and they told me that theirs come from the same factory as the ones from silverton but I will pay double for theirs... I'm not using water, never have to top up but then I also dont drive it all that much unless I do a long trip although even then I never top up coolant... but I will start watching it very closely. I cant do anything until next year anyway so I'll have time to test. I need to go get the chemical test done again to make sure sure...

I'm not saying that nissan here aren't any good but one 2 minute test at silverton and i have to replace gaskets.... when silverton do the test they have bright blue liquid in a tube that they put onto the radiator in place of the radiator cap. They force air into it and when it comes back out into the tube its supposed to change color if the head is leaking. Apparently if it's a bad leak or a cracked head the liquid will go yellow or brown. Mine went a faint grey in some places but it looked to me like some coolant just mixed with the test liquid... but I dont know anything about that stuff so i end up trusting what the guy says....

I suppose a compression test would be the definitive test

[Tinus lotz]

Ok the long and short is that the silverton test is bullsit really . Speak to any proper mackkie and they will tell you the same ...mabe your radiator is slighty blocked ? Put a heat gun and have a look if temps are the same all over ...the aftermarket radiator is 3600 here if they have stock .
Are your aircon one clean are you getting proper airflow there?

[Craig Lord]

Just to make it more confusing yesterday we drove 580km from gabs to tuli in 35 degree heat while towing a loaded trailer and the patrol performed normally doing 110 the whole way. This morning I checked the coolant levels and they are the same as when we left. yet 2 days ago I could barely do 100kmph without it heating up while it was empty....

As soon as I have time I'll take off all the hoses and check for blockages. Following that I'm going to book it in for a checkup at G tech as soon as I have a chance.. I still think it's a radiator issue but maybe Graham can do a compression test to be sure.