D4 7u cooling system

What is the best thing to use in flushing the cooling system? Pushed teraces up today, it was 95 degrees F outside, the temp on the D4 was on line between the green and red. What to do what to do.

Cat. have two types of cooling system flush products available, if you are 100% certain your radiator cooling fins are not choked with dirt and trash, and your fan belt is not slipping, one product is a fast acting acid, I believe you put it in your cooling system for only 40 minutes or so before flushing, while the other one is slower acting and is put in there for about 4 or 5 working days. Your thermostat might be jammed too, or your radiator might need "rodding" to clean the down tubes, or your temp gauge might be faulty, I'd pressure wash the external cooling fins myself first, and check the belt tension, before tearing it all apart, because with a air temp. of 95F you need 100% of that external cooling surface working, and double check your water temp with a thermometer to see if your gauge is working properly.
regards
Mike

Hey Mike, wasn't it you who blew out your radiator core when you pressure washed it? If the machine is showing signs of corrosion, I'd probably use a good steady stream from the garden hose. Until I heard about the damage done to the core, I would have used the pressure washer too. 👍

No, I've never done that Bruce though most my old Cats have shot cores more from external rock, stick or corrosion damage, in my opinion if the core isn't strong enough to handle pressure washing you don't want it on a working tractor because it will suddenly leak out in a few seconds when you are not looking and the escaping steam is the only warning you get that your red hot motor is about to start locking up, it has obviously passed it's use-by date if it is that weak, now a Parade tractor doing 2 hours a year is a different situation with minor weaps and drips and a almost porous core, and products like "Alumaseal" have worked well for me. You might be interested to know ROCORE recently quoted me about $US550 for a new D2 4U / 5U core, delivered anywhere in the U.S., and there are other companies like "General Radiator" who are cheaper still.

The D2 5U I recently rebuilt the steering clutches on has a core that looks like someone peppered it with a 12 gauge and #8 shot it was that weak with water pouring out everywhere, it would be half full in about 2 minutes, but two cans of an Alumseal type product called "Scotts Superior Radiator Sealer" sold here in Australia amazingly sealed all the leaks after only 15 minutes driving, but I wouldn't trust that core on a working tractor or with any one else driving it, no Sir, and for a few hours work and $20 of gasket material, and $550 for a new core, it's a no brainer to rip that old core out, the worst part is getting the rotted off bolts out of the lower radiator straps, that can be challenging, but not impossible.

My experience cleaning old Cat radiator cores, and I've done a few, is that my regular garden hose does not provide sufficient pressure at about 35 pounds to dislodge the amazing amount of old oily, greasy, baked in dirt and crud that chokes a core on a old Cat, in fact a 2 Ton I'm working on now still has it's original 1927 or 1928 core and even after a week of pressure washing that core for a few minutes each day, I was still getting crud dislodged from within the center, it amazed me how much kept coming out. Another thing I do is get one of those magnetic pick up things, for when you lose nuts or bolts inside a transmission, or under a tractor, and I remove the radiator cap on my old Cats and prod that thing left and right as far as it will reach, you will be amazed often at how many large flakes of rusty crud are laying on top of the core inside the top tank, on my RD6 I did the other day I got probably 2 full cups of rusty flakes that were effectively laying on top and blocking the water flow down the core, for the most part it was very thin sheets of cast iron delaminating off the radiator tanks and motor.

Interestingly, I pulled the liners on my D2 4U a week ago and found the lower water passage in the block between #2 and #3 cylinders completely choked with rusty flaky crud, and the lower water port from the block that leads to the base of the pilot motor was also fully choked with rusty flaky crud, which explained why that pilot motor started getting too hot quickly the few times I've run it, even though I spent hours rodding the the pilot motor water jacket and heads, and, I'd already sat a Citric Acid solution in that entire D2 cooling system for a week (flushing it every 2 or 3 days), so I was amazed at how much crud accumilates in these older Cat. engines, particularly those that were run on bore or well water, and not the fancy coolants we see now, and it confirmed that while cooling system flushes might be OK for maintaining cooling system function, they are not a reliable solution, in my humble opinion, to curing over heating engine problems.
regards
Mike

The problem with radiator flush and old radiator cores is more often than not you end up with a leak. You need to figure out what temperature your engine is operating at before you do anything. An IR thermometer is the easiest way to get started. Maybe you don't have a problem.

As for using a pressure washer to wash out your core's cooling fins, that's the last way I'd approach that issue. A water hose will work but its still water. Water and dirt make mud which can leave your core worse off if you don't get it clean. Run your engine up to operating rpm and use compressed air and a wand type blow gun to clean the fins of the core. The problem with the 7U is its has a puller fan. The compressed air method is much more effective when your machine has a pusher fan but it will still do the job.

Radiator on outside is clean, fan belt is tight, engine was rebuilt 32 years ago. This has the split radiator with oil cooler beside it. I just put this gauge in and is the part number for the 7u temp gauge.

Forgot to add I put a brand new Cat thermostat in it to.

This might be your problem. Where was the new thermostat made. I've heard a few complaints. I take it your old thermostat was not working properly.

Old thermostat was stuck part way open. I can watch my temp gauge and you can tell when the thermostat open when the engine gets warmed up, after that no way of knowing.

Sorry dont know where it was made.

The last thermostat I bought from a Cat dealer a year ago was printed on the box "Made in the USA" but the thermostat itself was stamped "Made in China".