Another "boiling" expansion tank story

Here is that chart. It’s always interesting to note that there is a minimum freezing point which is not at 100% glycol, a concept that is often misunderstood.

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Pure water removes heat better than an antifreeze mix so "it's complicated" when you're fighting cooling problems.

I also think it's your rad cap, BUT

I had an 89 Firebird, 2.8 V6 that ran warm (220) a lot of the time. I had the boiling tank, new rad cap didn't help. Turns out it was missing its air dams underneath, that force air up and through the radiator. Cobbled something together for it and it was a lot happier.

We lose these things on curbs all the time, and often chuck them, thinking they're meaningless.
 
My guess was going to be plugged radiator, failed fan clutch/electric cooling fan, WP impeller, or anything that could inhibit the radiator's ability to remove heat. A higher antifreeze concentration would likely make the problem WORSE! Like my old Renault Alliance I had with the bad cooling fan that blew the tank off the radiator (when I got stuck in atop & go traffic in summer)!
 
Well.... this morning I did 25kms at 2500rpm with no issue.
Then I did the same journey the other way (which included the uphill segment) at 2500rpm and no issue.
Did the 5km hill climb at below 2500rpm, due to a big rig in front of me, and no issue.

So, as the problem only seems to happen above 2500rpm on a hill, my mechanic has called "head gasket".
There is nothing to suggest a head gasket fault (creamy oil, steam out the exhaust etc) but that's his diagnosis.
Thoughts?
 
I'd go with plugged radiator too. I've had a head gasket go before (different vehicle) and I'd be expecting fluid to be drawn into the engine not expanding out. I've bought a chemical tester from amazon.es, so we'll see. It'll be with me on Tuesday.
 
I'm going with Thermostat failure, plugged radiator, or water pump impeller failure.

Hopefully the test will come back good for the head gasket.

Whats the condition of the coolant? When you drained some was it loaded with crud? Check for dead spots with IR gun.

Easy test for the water pump is to remove the belt and operate by hand, binding, loose shaft, etc.. May be able to feel broken impeller that way.

Replace the thermostat
 
Truck: Mitsubishi Shogun Sport 2006
Got a problem which started yesterday. Arrived at my farm gate and I could hear a "bubbling" from the engine compartment, so had a look. The overflow from the expansion tank was overflowing and both the tank and radiator were making "bubbling" noises. Dash temp was normal.
Added coolant in the expansion tank this morning and did a test run. Truck was fine for about 35kms until I got to a long hill, started going up and after a few hundred metres, I could hear the "bubbling" noise. Kept going for about 6kms (it's a long slope with steep and nearly flat sections) before stopping.

Been running the engine whilst stationary for a bit now and no "bubbling". Electric fan works, dash temp normal, oil clean. If I squeeze the top rad hose with the rad cap locked, I can push fluid into the expansion tank and with the rad cap unscrewed, no fluid movement, so the rad cap seems ok. Tried with heater blasting or aircon full on, with no problems.

So all I know is everything works fine until the engine is under load to climb a hill. Truck goes fine otherwise (no smoke of any colour), so I'm baffled. Any ideas anyone?

This truck has a hard life as a farm truck and I try to keep a preventative maintenance plan going for it. It passed its annual inspection a few days ago.

TIA
I know it's TBD for now, but I suspect the HG.

Had two cars (both SAABs, oddly enough, a V4 in a model 96, and the 2.0 L in late 70s 99) and a friend with a mid-80s or so Toyota Forerunner who had similar symptoms.

All were inconsistent in when symptoms would appear and none had the oil milkshake. In all cases, the culprit was the combustion chamber would leak into a water passage caused by a bad head gasket, causing the overflow tank to boil over. It was maddening as all get out because it was so unpredictable, and rather infrequent.

HTH and hope that isn't the cause, given the labor involved.
 
The local mechanic will do it. I can't do anything in a field. I've tried field repairs before and it's a waste of time. I had a hell of a job to get him to say "yes" because he's under the cosh with pre holiday car services. Been running around on my Yamaha Grizzly which unfortunately this morning has just split a drive gater. Rats! I've looked at new trucks but the thought of the sound of bushes on new paint has stopped that idea and I'm not paying a fortune for a 2nd hand truck with high mileage. There is a guy in Australia who has built an electric motor and drivetrain for my type of truck and am thinking about that. The 2 problems with that idea is that trees don't have electric sockets (and where I live in the village the road is 2.5m wide) and the volume of Spanish paperwork needed for the import and motor swap will probably be horrendous. Anyway, the mechanic is changing the gasket, getting the head skimmed and swapping out anything else (thermostat, rad cap, pump impeller etc) just to be on the safe side. I need a working truck for the harvests in September. At least my tractor is still working!
 
Had similar issues with an infrequently driven 2000 Miata. Chased everything down on the marginally effective cooling system, finally ID'd the culprit. It can be an air only leak. Tough to track down.
 
little off topic maybe.

I have done timing belt replacement (along with all pulleys, water pump, tensioners) on my forester 2011 with EJ25 DOHC turbo engine at 107k running.

I did accordingly with manual and Utube guys. And assembled back only to find out that it is now overheating when going for like 5km. When idling, it goes back to normal temp.
(Radiator was replaced a month ago.)

What could be the cause guys?

(I reused the coolant cuz its only a month old. But I spilled some and added 0.5L water instead, would concentrate of coolant degrade and cause this mild overheating?)

or any potential cause i can think off maybe overtightening new water pump? (really cant think of any other reason, help me pls)

Thanks for your reply
 
little off topic maybe.

I have done timing belt replacement (along with all pulleys, water pump, tensioners) on my forester 2011 with EJ25 DOHC turbo engine at 107k running.

I did accordingly with manual and Utube guys. And assembled back only to find out that it is now overheating when going for like 5km. When idling, it goes back to normal temp.
(Radiator was replaced a month ago.)

What could be the cause guys?

(I reused the coolant cuz its only a month old. But I spilled some and added 0.5L water instead, would concentrate of coolant degrade and cause this mild overheating?)

or any potential cause i can think off maybe overtightening new water pump? (really cant think of any other reason, help me pls)

Thanks for your reply
Did you replace the thermostat? They can stick, and / or outright fail. It's easy to replace, (in most cars), and it's a cheap place to start. You can even drop down in temperature a slight bit and see if that helps.

My older Ford F-150 came with a 195 degree thermostat from the factory. Several years later it started to stick on the initial warmup. So I replaced it with a 180, and never looked back. That was around 1995.
 
Did you replace the thermostat? They can stick, and / or outright fail. It's easy to replace, (in most cars), and it's a cheap place to start. You can even drop down in temperature a slight bit and see if that helps.

My older Ford F-150 came with a 195 degree thermostat from the factory. Several years later it started to stick on the initial warmup. So I replaced it with a 180, and never looked back. That was around 1995.
hi Bill. Yes, it was replaced with radiator. When idling or just turning on heater, temp goes back to normal area.

Does little more water in solution makes it that bad?
or should i try to bleed air for like an hour?
i did bleed the air for like 10minutes cuz it reached normal temp and air bubbles stopped.
 
hi Bill. Yes, it was replaced with radiator. When idling or just turning on heater, temp goes back to normal area.

Does little more water in solution makes it that bad?
or should i try to bleed air for like an hour?
i did bleed the air for like 10minutes cuz it reached normal temp and air bubbles stopped.
Bleeding never seemed to matter much in most of the older cars. But it can make a big difference in many of the newer models. I know my 5.7 HEMI V-8 has a bleeder valve or screw somewhere. And there is a type of "method" to use it.

To be honest it's the one reason I'm afraid to drain and flush the system myself on my newer Jeep and Toyota. On my older Ford, after a drain and flush, I would top off the new coolant mix, run it until it was good and hot. Then shut it off.

Overnight it would cool off, and the system would self bleed, and the level in the overflow tank would drop substantially. I topped it off, and I was good to go.

What concentration of antifreeze / water did you use? If it has too much concentrate it might run slightly hotter, but I can't see it causing an overheating problem.

And the fact it runs cool at idle, but gets hotter underway, is somewhat strange. Usually it's the other way around. Moving air through the system helps things stay cool.

As far as the bleeding, I know you can rent a coolant vacuum pump from most chain parts stores for a few bucks. I've never used one, but they can help in eliminating air voids in the system when you refill it with fresh coolant. They are quite common today. However I have never used one myself. Perhaps someone who has can chime in here.
 
Truck: Mitsubishi Shogun Sport 2006
Got a problem which started yesterday. Arrived at my farm gate and I could hear a "bubbling" from the engine compartment, so had a look. The overflow from the expansion tank was overflowing and both the tank and radiator were making "bubbling" noises. Dash temp was normal.
Added coolant in the expansion tank this morning and did a test run. Truck was fine for about 35kms until I got to a long hill, started going up and after a few hundred metres, I could hear the "bubbling" noise. Kept going for about 6kms (it's a long slope with steep and nearly flat sections) before stopping.

Been running the engine whilst stationary for a bit now and no "bubbling". Electric fan works, dash temp normal, oil clean. If I squeeze the top rad hose with the rad cap locked, I can push fluid into the expansion tank and with the rad cap unscrewed, no fluid movement, so the rad cap seems ok. Tried with heater blasting or aircon full on, with no problems.

So all I know is everything works fine until the engine is under load to climb a hill. Truck goes fine otherwise (no smoke of any colour), so I'm baffled. Any ideas anyone?

This truck has a hard life as a farm truck and I try to keep a preventative maintenance plan going for it. It passed its annual inspection a few days ago.

TIA

2.5 diesel?

Notorious for cracked heads and failed gaskets.
 
Hi...quick update. Yup the head on my Shogun Sport 2.5 deisel was cracked. Bought another one (pre assembled with cams, valves etc) a couple of weeks ago in Germany (721 euros delivered) and the mechanic is currently and gingerly nailing all the bits back together. I couldn't find one in Spain. My Yamaha Grizzly which I was riding around whilst waiting for my truck also died, so that's just sitting there at the mo... Bought a nearly new Nissan Navara NP300 to cover my bum in the meantime. I hate it and want my truck back. Expensive summer!
 
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