coolant/radiator issues

[dannypatrol]

HI everyone, hope you all had a good xmas. I went away to Coffs Harbour. Didn't do any 4wd but went on unpaved roads to reach campsites.
Yesterday I drove back to Brisbane, a 450ish km drive on which I drove most of the time 110ish km/h. Did it in 3 pieces with some 10min breaks. On the last bit, i stopped for fuel and noticed suddenly a lot of coolant disappearing out of mine outflow tube (the tube that clears it onto the road). Checking coolant levels, all seem to be fine, although hot but not boiling. This didnt worried me so I continued to drive the last 50km home. The temp gauge moved a couple of times between 1/3 and 1/2 but never further than 1/2way. Today checking the radiator and coolant bottle, both seemed very empty (eg. I could not see anything in the coolant bottle and radiator). I had to top up the radiator with 4 liters! and the coolant bottle as well. I wasnt parked level, but with front down but still expected to see sufficient in the radiator. There is nice flow through the radiator when the car is started and the hoses look fine.

Bit of history about the car. I bought it a while ago for a big lap which I am planning to do next year, it is my first car and I dont know much about engines so used this forum a lot to gain some knowledge. The car is awesome and it is amazing to just be able to drive on the beach etc (we dont really have that in the Netherlands).
I had on bribie some overheating issues (see an earlier treat) , which I solved with the help of a mechanic by replacing the viscous fan and thermostat. After that I had no issues anymore besides one time on a very hot day where my LPG wouldnt start right away but after four times (see another treat), but this was discarded as extremely hot weather.
Yesterday wasnt a really hot day, it was rather cool and it was raining a lot. I was running on LPG and doing 110km/h most of the time.
This kind of worries me that there are still some problems out there and I want to prevent to encounter a blown engine in the middle of no where on the big lap.

Anybody any advise?

[megatexture]

Mate I think you need a after market temp guage to see what its really doing.

Is your shroud in good condition and the right size for the radiator? I can't remember.
Or have you been bush and the radiator needs a clean out?
That radiator is huge I just can't see how you could be having issues.

[the evil twin]

The engine should be running cool as if it is raining.

The temp gauge should also be relatively steady.
A wandering temp gauge means problems.

Could be a few things and maybe a compression test is in order, how many K's on the vehicle.

If you were getting overheating before and have replaced the fan clutch and thermostat and if the shrouds etc are all OK I would be thinking of getting the Radiator rodded.
Just flushing them doesn't work all that well it is best to remove the Rad and get it serviced correctly.

[dannypatrol]

Mate I think you need a after market temp guage to see what its really doing.

Is your shroud in good condition and the right size for the radiator? I can't remember.
Or have you been bush and the radiator needs a clean out?
That radiator is huge I just can't see how you could be having issues.

yeah, I think you are right, need an aftermarket temp gauge. Was initially thinking of ecu thingy, but got put off by the price.
I hit some dirt road for 30min and it was a bit dusty, but then it poured rain for 3 days and it all looked pretty good. The only thing I can think of is that the radiator is partly blocked, but because it is all welded up, there is no way to check it.

When we replaced the viscous fan and thermostat everything looked ok (even the viscous fan wasnt that bad, what always worried me a bit, leaving the possibility there is another part contributing to the problem). But shroud looked good as well

[dannypatrol]

The engine should be running cool as if it is raining.

The temp gauge should also be relatively steady.
A wandering temp gauge means problems.

Could be a few things and maybe a compression test is in order, how many K's on the vehicle.

If you were getting overheating before and have replaced the fan clutch and thermostat and if the shrouds etc are all OK I would be thinking of getting the Radiator rodded.
Just flushing them doesn't work all that well it is best to remove the Rad and get it serviced correctly.

the temp gauge was relatively steady, it wandered three times in the last bit but within a very small range. I figured it might have been a bit of the cold water I added. Alternatively, it is likely I maybe even was running partly on air (considering I was missing 4l coolant).

I am unsure how a compression test is done but we checked for cracked head etc. I think you might be right about the radiator, it is just welded up so not an easy job but might be best indeed.

[megatexture]

That radiator looked near new when I saw it and I'd be surprised if its blocked internally but you never know.

You could even try flushing water through it in reverse (into the bottom and out the top) as sometimes that can flush out a fair bit but it would let you see if there are any traces of crap in there then decide if you want to get it rodded

[dannypatrol]

yeah can try that, cheers. The radiator looks pretty new but I am unsure at this point what else it can be

[mudnut]

I sincerely hope I am wrong, and I only have an RB30, but the signs that you describe are nearly exactly what happened to my vehicle. It turned out to be two split fire rings in the head gasket. The engine didn't miss a beat and the temp barely changed, but after a long trip, the water was forced out of the overflow, and it took a couple of litres of water. After the head gasket was replaced, the water pump seal gave way as it was the weakest link in the system.

[dannypatrol]

I sincerely hope I am wrong, and I only have an RB30, but the signs that you describe are nearly exactly what happened to my vehicle. It turned out to be two split fire rings in the head gasket. The engine didn't miss a beat and the temp barely changed, but after a long trip, the water was forced out of the overflow, and it took a couple of litres of water. After the head gasket was replaced, the water pump seal gave way as it was the weakest link in the system.

Dham that wouldnt be good. Any advise how to check on this? We checked for cracked heads by measuring the air but no visual inspection. You reckon it would be good to check the split fire rings and water pump seal?

[mudnut]

Following the advice of a mate who is an old school mechanic, I removed the water pump belt to stop the water being agitated and creating bubbles. I fitted a half bottle ( I used a threaded male to male joiner siliconned in the neck of an old coolant bottle) to the bleed point near the front top of the block. With the radiator cap on I then Idled the engine for a couple of minutes. When I revved it up (momentarily), the coolant was forced out of the bottle. But mine is an RB30, so a 4.5 is different. Also get the test done in as short a time as possible. I didn't let the engine run for more than 7 minutes, to avoid damage to the block. And the engine was cold before the test. And don't forget to refit the belt! The water pump seal manifested itself as a white salty stain at the bottom front of the engine, and also the smell of coolant when the engine was hot. Hopefully someone who has a 4.5 can tell you how to test it without causing damage.