Universal coolant in 7.3L Powerstroke van

[redguy34]

Hello,

Over the year I've owned my 01' Ford E350 7.3l PSD van with 309k miles. I've ended up with a mix of 3 coolants due to absent minded top offs after unrelated jobs. SuperTech and O'reillys all make, model, year coolant (whatever I could get my hands on & cheap) and what ever green coolant was originally there. Which based on the receipts I got with the van is from 2018.

I use SuperTech stuff for everything. But that stuff like 15w-40 oil and Mercon V. Is compatible. The coolant I'm not so sure. So what can I do now. And learn for the future.

Thank you,

Red

 

[Lubener]

Mixing varous brands of green coolant won't harm anything. I would be more concerned why you have to keep topping off your coolant all the time.

 

[redguy34]

The van is what would call a project. Through various coolant leaks, Replacing the radiator and all the things that require the upper radiator hose to be removed. In my humble opinion removing the upper radiator hose helps a lot with access in the tight engine bay. The downside is that through the thermostat housing coolant seems to rise out. Which I just catch in a drip pan and put in old bottles. Put new stuff in. But I lose probably a gallon everytime.

I am going to add Ford's SCA for diesel engines though now that I'm enlightened that it exists. Better late than never.

I don't think I'll ever have to worry about my coolant being too old though. At the pace I replace it. It'll never be more than 6 months old.

Red

 

[BC1]

That universal is not really the best option. Can you get to the block plugs easy in the van like the trucks? I would drain it all out and start again with either green (which you have to keep up on with SCAs) or a red ELC. You will need 4 gallons of concentrate and 4 gallons of water.

 

[redguy34]

I'm not entirely sure. Where are the plugs roughly? I can look. I ordered a wix coolant testing kit for 40 bucks. Comes with 50 strips should last me a while. And some Ford V8 SCA. I can always return that unopened if I don't need it. So I can measure and add what's needed if i did that. But anyways.

So don't just add SCA to what I have now? At least drain and replace with fresh green stuff?

Or red ELC? I've never heard of that. Is that the color of CAT EC-1?

Red

 

[redguy34]

I got my testing strips. The results are not good. 0 nitrates 50/50 mix so one goof thing and a ph of 6.5 duh duh duh! Yeah maybe the og coolant already had it? Guess I'm returning that SCA additive for ELC?

Thoughts?

Red

 

[BC1]

The drains are just behind the oil cooler cap/filter mount and above the starter. The 1/4" plugs not the 3/8".

The green has what you need in it already and will work for a while. I would return those SCAs and just run the ELC. Napa has whatever flavor you prefer on special every other deal flyer it seems.

Edit, Seems most folks use CAT EC-1 rated stuff but any should work. If you put the ELC in there you should get all the old out. Expect to spend all day doing it and be nasty at the end if you dont have a lift. No matter how fast you are crawling out, that hot water waiting behind the plugs is faster.

This is a decent write up.
https://www.dieselhub.com/service/7.3-power-stroke-coolant-flush.html

 

[kschachn]

I got my testing strips. The results are not good. 0 nitrates 50/50 mix so one goof thing and a ph of 6.5 duh duh duh! Yeah maybe the og coolant already had it? Guess I'm returning that SCA additive for ELC?

Thoughts?

Red

Re-test the pH and post a picture of the strip, if you would please.

 

[redguy34]

Re-test the pH and post a picture of the strip, if you would please.

I will tonight if I get the chance. If not tomorrow evening. Then I will post a picture.

Edit: It slipped my mind but I did take a picture yesterday. Not the best but here it is. They are wix testing strips.

Red

 

[Coolant Kid]

You don't need to change anything, what you're doing is just fine. Dexclones like the Supertech, O'Reilly and other cheap house brands (I'm running Napa 1EXT at the moment in everything I service) cover it all. These are based on Dexcool and GM uses it in all engines, including light/medium diesels. No SCAs needed. In fact, don't put that garbage in your system, all it'll do is cause nasty scaling issues.

 

[redguy34]

You don't need to change anything, what you're doing is just fine. Dexclones like the Supertech, O'Reilly and other cheap house brands (I'm running Napa 1EXT at the moment in everything I service) cover it all. These are based on Dexcool and GM uses it in all engines, including light/medium diesels. No SCAs needed. In fact, don't put that garbage in your system, all it'll do is cause nasty scaling issues.

What are you thoughts on the low Ph? Seems low to me. I will also test again this evening if I have time or tomorrow evening if not.

Red

 

[dnewton3]

The old 7.3L PSD engines should have regular treatments with SCA (supplemental coolant additive).

I'll expand on why I state this ...

Way back in the day when I worked at the Ford plant in Indy, the Navistar plant where the diesel engines were made was (literally) about 5 minutes away. So it was not uncommon to see those engineers out to lunch in the same places we'd go out. I had a chance to speak with one of the product engineers, because I was interested in getting an F350 with the 7.3L PSD at the time.

He told me that those engines need the SCA because it was prone to cavitation issues in the long term; these events can cause pin-point erosion of the exterior of the cylinder walls. The rapid explosion and collapse of the cavitation bubble will eventually eat away at the cylinder, weakening it. In extreme cases, it can literally cause pinhole leaks through the cylinder wall.

If you look in the old owner's manuals from those vehicles, there is a mention of SCA being needed (IIRC, every 15k miles ???). The 7.3L PSD is renowned for longevity, and despite most folks not using the SCA, it is important. The Ford specific coolants for that engine (essentially mimicking the Navistar coolants) already had the SCA blended into them. If you don't use a coolant with SCA blended into it, then you should be adding it.



Any "green" traditional coolant will work in the old 7.3L PSD as long as the SCA levels are good.

 

[redguy34]

The old 7.3L PSD engines should have regular treatments with SCA (supplemental coolant additive).

I'll expand on why I state this ...

Way back in the day when I worked at the Ford plant in Indy, the Navistar plant where the diesel engines were made was (literally) about 5 minutes away. So it was not uncommon to see those engineers out to lunch in the same places we'd go out. I had a chance to speak with one of the product engineers, because I was interested in getting an F350 with the 7.3L PSD at the time.

He told me that those engines need the SCA because it was prone to cavitation issues in the long term; these events can cause pin-point erosion of the exterior of the cylinder walls. The rapid explosion and collapse of the cavitation bubble will eventually eat away at the cylinder, weakening it. In extreme cases, it can literally cause pinhole leaks through the cylinder wall.

If you look in the old owner's manuals from those vehicles, there is a mention of SCA being needed (IIRC, every 15k miles ???). The 7.3L PSD is renowned for longevity, and despite most folks not using the SCA, it is important. The Ford specific coolants for that engine (essentially mimicking the Navistar coolants) already had the SCA blended into them. If you don't use a coolant with SCA blended into it, then you should be adding it.



Any "green" traditional coolant will work in the old 7.3L PSD as long as the SCA levels are good.

Ok. I do have Motorcraft V8 though I need another bottle. Since 1 pint only treats 4 gallons. I would rather flush with ELC when I can. Since it apparently doesn't need SCA.

I'm getting some conflicting info here. So adding SCA vs flushing with new ELC? Is my pH a problem? I would add SCA to hold over till summer then flush for ELC.

On that topic what are the odds something bad has happened? I've put 10.5k miles on it. Bought at 298k sits at 309k. No towing no heavy loads.

Thanks for all the replies,

Red

 

[BC1]

His 2001 7.3 PSD has cylinders bored into the block like any old gas engine. It does not have cylinder liners like some other diesels. Cavitation is not a problem on these. Some of the earlier IDI had issues not 1999.5+.

 

[Coolant Kid]

You're trying to find a problem that doesn't exist here, nothing is wrong, continue to do as you've done with the Supertech or any other cheap universal extended life coolant.

You don't need SCAs, that stuff is old, obsolete technology and it's garbage. It just coats the entire cooling system like a thermal blanket and at best, reduces heat transfer efficiency by about 11 to 14%. At worst, it builds up enough to create nasty scaling and can clog the heater core, radiator passages, etc. and will eventually lead to actual overheating. It's darn near impossible to get out completely once it's coated everything like that. Do not add that junk. Long ago, it would make sense that a Ford engineer would recommend that, but this is 2026 - SCAs are long obsolete and unnecessary with modern coolant formulations. Coolant companies continue to offer it for folks who simply can't wrap their mind around the fact that they're not needed any more. Just like how they continue to offer old school conventional Green coolant with silicates, it's really the last thing you want to add to an engine. I feel bad for folks who go out of their way to find that stuff, when the easy, correct choice is literally available everywhere, starting with your local Walmart.

You don't need diesel ELC. Like I mentioned earlier, GM uses Dexcool (which is what Supertech, etc. is) in all their Duramax diesel engines, with nothing additional needed. It, like all modern coolants, don't need nitrites or SCA to prevent cavitation. Doesn't matter if you have wet cylinder liners or not, Dex protects them all, while being cheap and practically maintenance free. Also, it's not just GM. For several years now, Ford specs Motorcraft Yellow (which is simply Prestone yellow bottle, rebranded for Ford) in their Powerstroke diesels with no additional additives needed.

Your test strip looks to be showing perfect results to me. No nitrites, which is good and what should be expected since you've been using Supertech, etc. The glycol concentration is at 50/50, again where it should be. I can't make out the ph scale labels in your photo, but if it's 6.5 that's fine. Everything is good, don't waste time or money doing anything different. Also, I'd add don't flush the system and waste perfectly fine coolant for no good reason, you're just wasting money and contributing to environmental harm.

 

[redguy34]

His 2001 7.3 PSD has cylinders bored into the block like any old gas engine. It does not have cylinder liners like some other diesels. Cavitation is not a problem on these. Some of the earlier IDI had issues not 1999.5+.

Wow the Google search AI overview blatantly lied to me. Which is not too surprising. It claimed that 7.3ls had wet cylinders.

You're trying to find a problem that doesn't exist here, nothing is wrong, continue to do as you've done with the Supertech or any other cheap universal extended life coolant.

You don't need SCAs, that stuff is old, obsolete technology and it's garbage. It just coats the entire cooling system like a thermal blanket and at best, reduces heat transfer efficiency by about 11 to 14%. At worst, it builds up enough to create nasty scaling and can clog the heater core, radiator passages, etc. and will eventually lead to actual overheating. It's darn near impossible to get out completely once it's coated everything like that. Do not add that junk. Long ago, it would make sense that a Ford engineer would recommend that, but this is 2026 - SCAs are long obsolete and unnecessary with modern coolant formulations. Coolant companies continue to offer it for folks who simply can't wrap their mind around the fact that they're not needed any more. Just like how they continue to offer old school conventional Green coolant with silicates, it's really the last thing you want to add to an engine. I feel bad for folks who go out of their way to find that stuff, when the easy, correct choice is literally available everywhere, starting with your local Walmart.

You don't need diesel ELC. Like I mentioned earlier, GM uses Dexcool (which is what Supertech, etc. is) in all their Duramax diesel engines, with nothing additional needed. It, like all modern coolants, don't need nitrites or SCA to prevent cavitation. Doesn't matter if you have wet cylinder liners or not, Dex protects them all, while being cheap and practically maintenance free. Also, it's not just GM. For several years now, Ford specs Motorcraft Yellow (which is simply Prestone yellow bottle, rebranded for Ford) in their Powerstroke diesels with no additional additives needed.

Your test strip looks to be showing perfect results to me. No nitrites, which is good and what should be expected since you've been using Supertech, etc. The glycol concentration is at 50/50, again where it should be. I can't make out the ph scale labels in your photo, but if it's 6.5 that's fine. Everything is good, don't waste time or money doing anything different. Also, I'd add don't flush the system and waste perfectly fine coolant for no good reason, you're just wasting money and contributing to environmental harm.

It does seem most of the internet agrees with you. I could just keep running this stuff. However I will still flush it in the summer. Because admittedly it is a scientists mixture of old and new coolant.

I guess I can't make everyone happy just have to choose one. So I'll just run what I have. If cylinder cavitation was gonna happen. It should've by now. And it is a 300k van. No one's gonna cry if the motors takes a dump.

I will post if anything major happens to the motor. Like it blowing up.

Red

 

[BC1]

I agree with no SCAs because you have to test and keep up.

You will be fine until summer. Then you can put that more of that all makes all models in your iron head iron block 7.3. After all it is good enough for duramax aluminum heads and 6.7 ford aluminum heads so what could go wrong.

Or you could put the red ELC like all the commercial trucks/equipment with iron heads.

 

[redguy34]

I'm gonna flush with red ELC in the summer. If I wasn't clear. I will say I disagree with the all makes models years marketing. Because someone like me is gonna come along and be like. Im gonna put this in my powerstroke diesel. Then its really is no good for certain motors than it's not true!!! Maybe I should've know better that there's no such thing as truly universal coolant but darn.

Stupid companies.

Red

 

[CDX825]

Run a coolant that meets Cummins CES 14603. This means the coolant is compatible with older seal and gasket materials.

 

[redguy34]

I like the sentiment. And I can look for coolant that meets those specs + CAT EC-1 or similar or just ELC coolant. But somethings telling me between me and the last owner. Running the wrong coolant for a loooong time. Theres no saving or prolonging the life of any seals that are ready to fail. I'll just learn the hard way. If/when theres oil and coolant mixing. Or I have coolant pouring out of the water pump.

But honestly if this van gives me much more trouble. It may well go to the junkyard in the sky. Since I put 4k in parts into it last year. I can't keep doing that forever.

Red