1994 Cooling Upgrade

[Iain]

I know this has been beat to death in this forum, but I have to ask the Stupid question.

When upgrading my 1994 to a dual thermostat type cooling system with a high volume pump. Is there anything else that I need other than the cooling upgrade kit (I am thinking of buying from Peninsular)? Is there any modifications that I will need to make? Will the stock radiator handle the higher flow?

I will probably be changing the timing chain as I have about 250,000 kms on the engine and it will probably be pretty much worn out.

I am planning this in about 3 months on my holidays so I want to make sure that I have all my ducks in a row!

Thanks in advance everyone! smile.gif

[markrinker]

Stock size radiator will work fine, but you might want to replace/re-core to get maximum results from your efforts. At a minimum, remove it and make sure it is cleaned of bugs, along with the A/C condensor, tranny cooler, and oil cooler.

Stock fan will suffice unless you plan to pull super heavy loads, live in desert southwest, or high altitude towing. You can use a plastic Duramax fan - don't know much more than that.

An aftermarket fan clutch is important. GM's 'Heavy Duty' unit still kicks in too late, IMHO. I have installed JK's and it works great with the stock 1994 fan/radiator/shroud.

Are you planning to swap in a Gear Vendors gearset in place of the timing chain? I wish I had when I did the motor swap on #2...

[nigeljones]

I just completed this weekend the cooling upgrade and replacement of the timing chain in my Suburban. :D

I havn't wrenched in a while but it took me 3 days to complete the task. I did not use the DSG gears based on the advice of others and the cost due in part to the miles on my truck which seem's to be similar to yours.

The job went well and it's fairly straight forward, however, I didn't think I would have to remove as much as I did that's where the time comes into it. :eek:

My only difficulty was the new thermostat's I have never seen or used the rubber gasket set up before. I first wondered why the thermostat at 54mm dia didn't seat in the 58mm housing and what was I supposed to do with the rubber gasket. It's not like the single thermostat setup that were all used too. :confused:

The rubber gasket fit's around the outer flange of the thermostat which seats very nicely into the housing. . Needless to say I didn't get it right the first time and it leaked something awful. Once I corrected my mistake it worked like a charm. redface.gif

I did swap the fan/clutch to the Dmax style and I ended up trimming the shroud on one side.
At the end of my drive way there is a small drop off on to the road and when the truck twist's across it (body flex), that was enough for the fan to touch the shroud.
With the new fan you can really notice the suck thru the front grill. smile.gif

Also do yourselve the favor and replace the lower rad hose. Mine looked OK but it's peace of mind.

The last thing that comes to mind is that you need to loosen the power steering/compressor bracket to get the crank sensor out. Just back out the bolts a little and it will pivot enough to get the sensor out and save taking something else off. ;)

They say that if you replace the timing chain remove the crank sensor etc. the vehicle will have to be retimed. I was concerned that it would not start but it fired right up. The timing is off and will need to be addressed but that's the next project. smile.gif

Good luck

[Iain]

I am thinking of putting in a gear set instead of a stock timing chain. It is a few $$$'s but it sounds like everyone is very happy with the ones they have installed. I am assuming that it makes a big difference to the accuracy of the valve timing and is more reliable.

Does the engine have to be re-timed after the crank sensor is removed or does the computer (1994 6.5TD) "re-learn" and do the re-timing itself?

[damork]

Iain,

You should have the timing re-checked. I went the gear route and installed a new pickup sensor at the same time. The timing needed some tweaking.

[Kennedy]

Originally posted by Iain:
I know this has been beat to death in this forum, but I have to ask the Stupid question.

When upgrading my 1994 to a dual thermostat type cooling system with a high volume pump. Is there anything else that I need other than the cooling upgrade kit (I am thinking of buying from Peninsular)? Is there any modifications that I will need to make? Will the stock radiator handle the higher flow?

I will probably be changing the timing chain as I have about 250,000 kms on the engine and it will probably be pretty much worn out.

I am planning this in about 3 months on my holidays so I want to make sure that I have all my ducks in a row!

Thanks in advance everyone! smile.gif The injection return line across the front will need modification, or replace it with a 1997 model.

It is simple to clip the hard line and splice with hose. I also include the heater quick coupler fitting in the kit as they are so prone to failure.

[More Power]

On one hi-cap cooling upgrade I did (1992-95 year truck), I bought a new fuel return line harness made for the 1997-99 engine, thinking it would fit without mods. It didn't, because of the different engine accessory brackets. The newer fuel return line harness is made for the 1996 or new accy brackets.

I wound up re-shaping the original fuel return line harness, and added some hose or wiring loom to protect the tubing harness in areas where it might rub against metal. No biggie - works just fine.

MP