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Post by ellisr on Nov 25, 2008 13:28:52 GMT 11
I guess this is a follow on from a previous thread a month or so back.
97 Bighorn with 4JG2 was heating up going up hills but found the viscous fan was not working correctly - fixed this up.
Ive now done a big trip towing the boat (1200kg single axle trailer) and still find that when you hit a hill (like the Lindis Pass in Sth island) the temp gauge slowly goes from normal half way between C and H up to at least 3/4 towards Hot. Once you go over top of hill and decend, the temp gauge goes back to normal again. Im very careful not to thrash it and make sure im in the right gear on the auto. Im a little worried that given an even longer hill the temp could creep up to the danger zone of Hot on the gauge. Is this normal ?
How have other members found temperature on this engine when towing up hills ??
Are the 3.1 Bighorn's prone to heating up a bit due to small radiator size or the like ??
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Post by geeves on Nov 25, 2008 14:33:57 GMT 11
The 3.1 is known to overheat for no apparent reason and fitting a larger radiator frequently does little to fix. This really applies more to lifted wagons or hot climates. Im assuming yours is standard and the trip up Lindus Pass wasnt in January so neither of these should apply. They are also prone to cracking heads.
Things to check
Check that all the sealing is in place around the radiator and that the cowling is a good fit. This ensures that all air through the grill actualy goes through the Radiator. Witchdoctor was chasing an overheating problem for 3 years before trying this Even I didnt belive the difference it made.
If you havent done this already fit an aftermarket oil cooler on the auto. All autos should have this done if used for towing heavy loads. I would fit it so the oil is split between the factory cooler in the radiator and the aftermarket cooler rather that through one then the other. This is for 2 reasons. A: the auto needs some engine heat to warm up when cold This prevent rough shifting and allows it to work more efficiently.
B: should one cooler block the other still works
Get a headgasket leak check done. Most garages do this with a very simple test
1200kg is a heavy trailer and Lindis Pass is a more nasty hill than it looks especially going from the Cromwell side because the topography makes it look less steep than it really is and the straights between corners encourage you to accelerate more than you would normally
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Post by ellisr on Nov 25, 2008 19:00:12 GMT 11
When you say sealing around the radiator what do you mean ?? .....and the plastic cowling - is this the main cowling that encapsulates the viscous fan, does it work best when sealed right up to face of radiator ??
Also one one other thought - electric fan/s in front of aircon condensor ..... what do you reckon ??
Cheers
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Post by geeves on Nov 26, 2008 6:05:55 GMT 11
Extra fans cant hurt
The sealing is anywhere that air can get round the radiator. There is a rubber strip around the bottom the makes a massive difference.
Also incorrect injector timing can cause overheating
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Post by James W on Nov 26, 2008 19:50:53 GMT 11
might be a stupid question... but is the radiator clean? inside and out? it can be amazing how many bugs get caught in there and can cause overheating problems
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Post by ellisr on Nov 27, 2008 7:43:49 GMT 11
Yes - radiator is nice and clean outside. Vehicle has low kms and a visual of the inside with coolant removed from what you can see down the throat looks like new !!
I didnt mention that there are fog lights on the bullbars that are in the path of airflow. dont know how much difference this makes ??
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Post by geeves on Nov 27, 2008 11:39:38 GMT 11
If you dont use then take them off. My wagon had huge lights on it when I got it and they never worked so I removed them and the running temp did drop a little
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Burty
Isuzu Baby
Posts: 28
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Post by Burty on Dec 9, 2008 10:19:53 GMT 11
Snap - the only time my 95 MU 4jg2 has ever overheated has been going over the lindis. The last time it was the start of a 'problem' - now its in the garage getting a new turbo installed whilst I pray the problem is not the injector pump.
The engine went right back to normal temp on the downhill Lindis tho.
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Post by Roger on Dec 17, 2008 19:24:34 GMT 11
There could be crap in the radiator or thermostat stuffed.
While my injectors were getting done I got the radiator flushed. Come back looking brand new.
Cost me extra $70 but I tell you what, my normal temp reading is lower than before and will rise to where it used to be when pushing it hard.
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Post by ellisr on Feb 16, 2009 14:06:13 GMT 11
Well wouldnt you know - 50% of the cooling tubes in the radiator were blocked according to the man at the radiator recon shop !!
The radiator looked sooo clean looking into the top tank, so really deceptive.
Had radiator tubes "rodded" out and what a difference - temp gauge doesnt even move now from position of just below half mark on gauge.
Here is a good tip.
Drive around until motor is completely warmed up and thermostat has opened circulating coolant. Park up vehicle,pop the bonnet and immediately rub your hand across face of radiator on the engine side (small hands easier as you need to get in between the fan blades)..... If there are cold spots in different places across the face then chances are you have partial blockages like i found. This is what prompted me to take the radiator out and to a radiator shop to find out my problems !!
Cheers
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Post by Yarno on Feb 16, 2009 17:12:30 GMT 11
Well wouldnt you know - 50% of the cooling tubes in the radiator were blocked according to the man at the radiator recon shop !! The radiator looked sooo clean looking into the top tank, so really deceptive. Had radiator tubes "rodded" out and what a difference - temp gauge doesnt even move now from position of just below half mark on gauge. Here is a good tip. Drive around until motor is completely warmed up and thermostat has opened circulating coolant. Park up vehicle,pop the bonnet and immediately rub your hand across face of radiator on the engine side (small hands easier as you need to get in between the fan blades)..... If there are cold spots in different places across the face then chances are you have partial blockages like i found. This is what prompted me to take the radiator out and to a radiator shop to find out my problems !! Cheers Had this happen to our Vienta (Camry V6) it was always overheating, got the radiator rodded (pulled apart and cleaned) and when we got it back the fans wouldn't even turn on with the car just idling with a very slight breeze. Makes all the difference. |
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