Loosing coolant

[Steveindar]

Hi All,

My 1HZ has been loosing up to 1 liter of coolant per trip/day. I noticed some staining on the rad from the plastic header so pulled the rad and stripped and cleaned the header gasket etc. All together and no more leaks there, but...engine is still loosing coolant. There are no traces of it leaking from pipes or welsh plugs or such. No oil in water or water in oil. Where is it going? Where/How to look for the problem? Could it be head gasket leaking direct through to piston under pressure?

Steve

 

[Gav missin]

Hi. I had a 1hz several years back. That had cracked the head between the water jacket and the exhaust valves. Check for pressure in the water system. Or get a sniff check to confirm.

 

[Tractionman]

Agree with Gav. I had it on the old 2l-te lump, and the tell tale there was the pressure in the system forcing coolant into the header tank, and then out of the overflow. I could see it bubbling in there, and could smell exhaust fumes in the header tank. There was some 'wet at the tailpipe too.
Head was cracked in 4 places and was leaking coolant as Gav said.

 

[Steveindar]

Damn! Hope it's not so serious. Got some advice today. Tie a plastic bag to the overflow pipe and go for a drive and see if coolant is actually passing the rad cap. eliminate one thing at a time I suppose.

 

[Tractionman]

Hope so too Steve. Also take rad cap off and if problems, coolant will be frothy and just keep on pumping coolant out, but that bag trick will do the trick without any mess. Fingers crossed for you.

 

[Grimbo]

Do you have the rear passenger heater ? the pipes run under the body and can drip water without you noticing the loss and as it's not under the normal engine area is easily ignored as "not from my truck" when you notice damp on the ground .

 

[Tractionman]

Another good thought there Grimbo. Something like that is preferable to head problemss, and can be blanked off or pipes replaced without much expense or trouble.

 

[Gav missin]

You jogged my memory now. These pipes were leaking on my 80 1hz. This is what caused my cracked head.

 

[Steveindar]

Hadn't thought to look at the rear heater. Not exactly needed here in the tropics.
I borrowed a mates pressure tester and pumped the system up to 15psi and only noticed a very slow pressure loss. Like 1psi in 10 minutes. I would put that down to the tester connections rather than the system. Test was done with cold engine. Can this be done with engine warmed up? Don't want to damage the tester.

 

[Grimbo]

Yes you can test the engine warm.....the tester is only creating pressure by pumping air into the top of the header tank or Rad .....

Do you have the rear heater ?

Another thing you could try is putting some UV dye into the coolant then looking over the vehicle with a UV lamp and glasses ....we use it for leak detection on engines and transmissions as well as air con systems....

Are you running antifreeze in the tropics ? ...... not a daft question as it is also a corrosion inhibitor ;-) antifreeze will normally leave a stain at the site of a leak as it evaporates on a hot engine.... a small dripping leak that stops when the engine isn't running can be difficult to find if the evidence evaporates as you drive .

 

[AndycruiserguyLomas]

You could try looking at the water pump, It could be leaking slightly and evaporating before it gets to the drip stage. Just an idea to add to other suggestions.

 

[frank rabbets]

Give it a good rev 5 seconds when cold. Then stop the engine and quickly pull the rad cap off. There should be no pressure in there.
I guess your heater matrix is not leaking?

 

[Steveindar]

Been slack this weekend, Friday night was a wine tasting event, so that took care of any Saturday work. Sunday the misses insisted on going fishing so I took my KTM and took the loooong way around to the dam. I'll get more active this week.
I did notice that when starting the car cold with rad cap off the coolant would rise up and overflow. I'll take a vid. Doesn't seem right to me.

 

[Steveindar]

I made a short vid but technology got the better of me. Too large to upload. It clearly shows small bubbles on start-up and then the level of the coolant rising slowly until it overflows.
What now?

 

[frank rabbets]

You will get all sorts of bubbles and overflows with the engine running so that is no guide. The definitive test is to wait until the engine is cold, top the rad up, put the lid on and start the engine and rev it at 3000 rpm for 5-10 seconds. This way you are testing the head gasket which, if failed, will pressurise the system prematurely. Then stop the engine and remove the rad cap. There should be no pressure in there as in a cold engine condition, which it still is. If water and bubbles spray out the head gasket has failed.

 

[Steveindar]

Gotcha!

 

[frank rabbets]

Yes if the engine is running so is the water pump which causes all sorts of turbulence.

 

[Tractionman]

Depends on the state of the head gasket if blown, or cracks in the head as to how much will actually be forced out of rad. As mine had 4 cracks, probably amounting to extreme pressure, coolant pumped out of rad and kept coming with froth.
Did you try your plastic bag trick ?

 

[Steveindar]

OK, did the cold start and rev thing. When removing rad cap there is no spray, but seems to be a slight vacuum and level has dropped by a couple of centimeters. Added about 250ml, cup, and tried the cold start and rev again. Same results. Needed to add a cup full.
I did a sundowner trip, not more than 10km's and removed cap whilst engine running. Slight pressure but nothing serious. Watching the fluid in the radiator there is pulsing in the radiator and level goes up and down. Also the overflow bottle was full. I'll try a new radiator cap again. We can only get look-a-like stuff, probably chinese knock-off. It will have to do so long.
Any ideas?

 

[Tractionman]

Some movement of coolant in the rad is normal, with vibration and the water pump working.
I am not familiar with yours, but does it have a rubber hose fixed to the underside of the header tank( overflow bottle). If so, check it hasn't dropped off. If it has, when there is expansion in the coolant, excess is pumped out of radiator into the bottle, when system is cooling that excess is then sucked back into the system.
If there is a pipe and it's fell off, coolant will continue to fill the bottle, but not suck it back up