Problems in Oz

[6.5 rangie]

G'day, first post here for myself from good ol Aussie land.
Have a few problems with my 6.5 in my Rangie, where do i start.
Well, with the car idling it sits on around 90-92 degrees Celsius(195f ??), cruising around its the same and then all of a sudden it goes up to 110-115c, and i notice oil pressure drops of a bit. Stop the car for a couple of minutes and then its all OK again. Engine has been re ringed and bearinged, new injectors, pump, thermostats, radiater, etc..
Its a 96 model out of a GMC pick up (i think), dual thermostat, high flow water pump (reverse rotation), mechanical injection pump, T700 auto.
Radiater is a 4 core out of a Nissan Patrol (plenty big enough)
Any help or advice would be great.
Thanks

[nev62]

Gi'day. This reply is not so much in the way of help but just what I have to keep the heat at bay (91 6.5 block, heads from 6.2 Toyota auto).

I have dual thermos in front and normal fan at rear, engine oil cooler and two smaller trans coolers in front of the radiator. my normal running temp is between 145F and 165F. When under load up long climbs or hot days (30C and up) it will climb to 200F. The only other thing I have not tried is a shrould around the rear fan which I'll have to custom make). Not much help like I said but at least you know your not the only one in OZ with cooling problems ;)

[6.5 rangie]

Could it possibly be an airlock?
Does the thermostat crossover bypass hose have or need a restricter in it to improve radiater flow when the theromstats open?
Thanks for any help
Damien

[a5150nut]

Did you bleed the air out the top of the thermostat housing? An air lock could be causing this.
As far as a restrictor, I didn't have any when I changed my 94 to duel therms.

[gmctd]

You guys should probably get together for some comparo, but I'm thinking that Patrol radiator does not present enough frontal area for required air flow - how does it compare to the oem GMC radiator for h x w dimensions?

Also, the heater connection between the t-stat crossover and the lower radiator hose is necessary for proper coolant flow, as is the 1" hose between the t-stat housing and the waterpump - that is a constant bypass, or constant recirculation, system, provides constant coolant circulation thru the block, whether the t-stats are open or not.

If the transmission cooler is in one of the radiator tanks, disconnect it and provide an external cooler, to reduce the thermal load on the coolant.

If the trans does not run hot, connect an external cooler in series with the in-tank cooler - out of the trans, thru the external-cooler, into the in-tank cooler, out of the in-tank cooler and back to the trans.

The additional external cooling should put cooler fluid thru the radiator, further reducing engine coolant temps.

This will work particularly well if you have a separate electric fan on the external trans cooler

An additional fan-over cooler in the return line will ensure the trans gets only cool fluid

Also, you must use the Rover temperature sender for accuracy

[6.5 rangie]

The radiater measures 770mm x 500mm, its a new 4 core aswell.
The guage is a VDO brand with VDO sender.
All the hoses are as you've said ie.. heater etc..
Auto is on seperate cooler.

What i have just found is that when i bring the revs up th top radiater hose sucks in, so i'm guessing this is my problem. When just cruzing along slowly all is well, but give it a bit and she heats up.
Will put a new hose on a take it for a run.
Thanks for your help
Damien

[a5150nut]

A lot of the upper hoses have a wire coil inside to keep them from colapsing.

[6.5 rangie]

Radiater hose fixed, and still happening.
Took it to a mates house to do a check on possible head gaskets or cracked head and all came up fine, then we stood back and looked.
In the front of a Rangie you have a smallish grill, well infront of mine i also have a trans cooler, a oil cooler, a high mount winch, in front of that a license plate and a big bull bar. So not a lot of room for air to travel through.
So tonight i have moved the license plate lowered the trans and oil cooler to get more air flow (can't do much about the winch though). Will see how this goes tomorrow.
Does anyone recommend running a small electric fan on the oil cooler, as mine is now sitting sought of behind the bull bar.
Thanks again
Damien

[gmctd]

I'm quite frankly having some difficulty with the overall situation there, down under.

Baro is avg 14.7psia around the world - let's say 15psia, because numbers with dots make my head hurt :confused: .

The 6.5 coolant system is capped at ~15-17psig, which is on top of Baro, for about 31psia.

Everyone see where I'm heading with this?

For Baro pressure to collapse the upper radiator hose means that coolant pressure in that system is less than Baro - you're somehow running a vacuum in a normally pressurized system!

Would tend to indicate some very severe blockage to coolant flow, possibly at the dual t-stat housing - didn't happen to leave a long-forgotten shop-rag stuffed in the water passage(s) to help keep critters out while building the truck, didja?

Again, perhaps you and Nev should get together for a pow-wow, maybe a walk-about to determine whassup, eh?;)

[kaylabryn]

Might want to make sure that the water pump is correct because if the upper radiator hose is sucking down then it is under vacuum. This is why they put the wire in the lower hoses to keep this from happening under high flow. Even if the system is under pressure the lower can suck down when stats are wide open. So if the pump is flowing wrong direction it will suck upper down. If you are not loading this thing with weight I do not see that putting around should heat it up unless you have a restriction or air in the system. I would take the upper hose off and watch when the stat opens that water exits and does try and suck in. !!!!Warning!!!! stand back so you do not get burned with coolant or water.

[gmctd]

Good point, and highly likely - specific waterpumps for

Serpentine belt = ccw waterpump rotation.

V-belts = cw rotation

[nev62]

Hey rangie, was just checking out the specs is the manual and your motor is not running all that hot.......

Oil operating temp (normal) is 180f to 260f (82c to 126c)

Cooling system temp (normal) is 190f to 230f (88c to 110c)

[DA BIG ONE]

Radiater hose fixed, and still happening.
Took it to a mates house to do a check on possible head gaskets or cracked head and all came up fine, then we stood back and looked.
In the front of a Rangie you have a smallish grill, well infront of mine i also have a trans cooler, a oil cooler, a high mount winch, in front of that a license plate and a big bull bar. So not a lot of room for air to travel through.
So tonight i have moved the license plate lowered the trans and oil cooler to get more air flow (can't do much about the winch though). Will see how this goes tomorrow.
Does anyone recommend running a small electric fan on the oil cooler, as mine is now sitting sought of behind the bull bar.
Thanks again
Damien

If any of your coolers are not in the airflow there are a few options,
1) coolers w/fan & thermostat control "B&M Supercooler": http://www.summitracing.com/
2) Air intakes w/hoses directed at coolers: http://www.butlerbuilt.net/airmanagement.html

I had major blockage of airflow ater installing a winch and bumper, scoop under bumper helps.

[6.5 rangie]

Nev, fixed most of the problems, it is mainly due to airflow through the radiater.
The shroud i made for the thermos was stopping airflow at higher speeds.
Now it sits on around 90-95c at 100kph.
BUT when in the bush thats a different story, 120c +, so i need to make a few changes here. Was thinking of a direct drive fan (no room for a clutch fan) and move the thermos to in front of the radiater.
Aslo will looking into getting a gauge to read my EGTs as my pump has been turned up, will this cause it to run hot quickly when giving a bootfull?

[nev62]

Nev, fixed most of the problems, it is mainly due to airflow through the radiater.
The shroud i made for the thermos was stopping airflow at higher speeds.
Now it sits on around 90-95c at 100kph.
BUT when in the bush thats a different story, 120c +, so i need to make a few changes here. Was thinking of a direct drive fan (no room for a clutch fan) and move the thermos to in front of the radiater.
Aslo will looking into getting a gauge to read my EGTs as my pump has been turned up, will this cause it to run hot quickly when giving a bootfull?

this is the setup I'm running (a direct drive fan and dual termos in the front). I have an oil cooler attached to the bonnet sitting under some flutes which also helps. My temp rises fast under heavy load to around 98c but is also quick to drop back down.

More juice and air = bigger bang = higher temps

I think I my have the problem where mine runs a little too cool at times. That helps to coke things up a bit.

You in Syd? Going to Appin? If so I might chatch up with you.

Cheers

Nev

[6.5 rangie]

Sorry Nev, i'm on the Mornington Peninsula in Vic, Appins a bit far for me.
I think i'll try a fan on the cooler aswell.

[nev62]

Might see you at chrissy, going down for a few days. Son is near Dandy and Brother is in Hastings :D