Gooey coolant

Fey!

I opened the bonnet of the surf (3rd gen 3 litre) the other morning to check coolant levels, and found in the overflow bottle what appeared to be brown, oily muck. Opened the cap on the rad to find the same thing.

In a panic I checked the indise of the oil cap and the dipstick, but thankfully all I found there was black oil.

I got a mechanic to look at it (not my usual guy), and he immediatly said that I had a cracked head, common to these 3 litre engines, and that it would basically be a replacement engine job.

The surf had been sitting idle for a couple of weeks while we were away, and the coolant was clear at that stage. After we came back I had only been doing short 2km or so runs before the coolant turned to sludge. It hadn't overheated, and it wasn't down on power or fuel consumption (my fuel consumption is improved by 20% at the moment after a dose of STP diesel treatment a couple of fills ago; I had been gettin 400km to the tank, and I'm currently getting 500. Might try diptane soon, as I've been hearing good things about it).

Because of that I hoped that it was only gunk coming to the top, so I got the coolant system drained. On Monday it was flushed about 4 times, and the same again today. It now has a proper antifreeze mix, and they did some kind of vapour test to try and detect if there was any oil getting into it this morning before they flushed it again, and that test came back clear.

Will sort out a compression test in the next few days for peace of mind.

Has anyone else gone through this?

If the oil level hadn't dropped it may well not have been oil mixing with the coolant. As it was idle for a while it may be resonable to presume the coolant was old and the anti corrosive protectant/inhibitor stuff was minimal in it, a bit of corrosion occurred and then was mixed through the system when put back in use.

If they did a sniff test to verify the hydro whatever yokes weren't present than gases aren't getting into the coolant, HG should be fine.

Any idea what the coolant was like before sitting idle for the few weeks.

Nissan doctor

Certainly points at a headgasket. It may also be a problem with the oil cooler if your hilux has one.

As james said, a snif test is the first port of call. This will immediately tell you if the headgasket is gone without any guess work.

101sean

I'd go with what James said, old coolant, sludge settling out and then only doing very short runs won't have helped. Give it a good hard run keeping an eye on the temp gauge and see how the coolant is then.

Fey!

Someone else suggested that the transmission cooler may have leaked into the radiator; it's built into the main radiator.

I hadn't flushed and refreshed the coolant since I bout it 18 months ago, so RoaverJames' suggestion may well be on the mark.

I think that what they (thye garage) were describing to me was a sniff test, and that came up fine.

Thanks for the replies.

kermitpwee

Fey! wrote: »

Someone else suggested that the transmission cooler may have leaked into the radiator; it's built into the main radiator.

It's a common enough problem alrite.