1995 G30 "Third Oil Cooler Line" ??

[Ziabeam]

Flying to Minnestoa from Florida in a few weeks (August 19th) to fetch a '95 G30 Cutaway van. It's the style that looks like a van chopped off behind the cab with a three door cargo box behind it. I'm unable to examine it, hence my current inquiry.

Neither Leroy of Leroy's Diesel, or Diesel Site's Blue-Ribbon tech's have been able to answer this question. According to Leroy, he is willing to fashion a complete oil cooler/oil line ensemble if I'll give him each configuration of the 3 lines. Problem is I can find no indication of there being a third line for any G30 van other than the gasoline V8's. The only lines I see anywhere for the G30 diesel with a 6.5L are the upper and lower Dorman 625-110 and 625-109 (GM 12472304 / 12472305).
Zero hints of a third line. Leroy sounded very confident a third line that interfaces the engine coolant radiator to the standard oil cooler is in the mix.

Leroy is able to run with my findings, and fab up a G30 specific ensemble if I can figure this out. That way I can prep the van for a trip from Minnesota and back to Florida via Wyoming and Arizona. A long way to drive on what may be 29 year old oil lines.

Any insight would be greatly appreciated.

Ed
P.S. (Edit) Leroy doesn't swear there's a third line, only that he thought there oughta be one. To be frank, I'll be delighted if we find out the 1995 G30 6.5LNA does NOT in fact have a third line, which would mean I can toss the TWO Dorman lines I purchased online today after measuring them for Leroy's requested dimensions, and higher quality lines he provides.

[Ziabeam]

Update;
Seller of the van (1,300 miles away) crawled under and reported the following;

Appears as though there are only two oil-cooler lines from the factory, both of which enter and depart the radiator, with NO separate oil cooler. Leroy's diesel was updated. This seems to indicate any instance of a third oil cooler line found in a G30 van application would likely be the result of a post-factory upgrade wherein the end user ADDED an external oil cooler into the mix. Hope this helps anyone else who might encounter this head-scratcher. If I find out anything to the contrary, I will update here.
Shout out to Leroy for guidance which helped us both learn a thing or two about how the diesel equipped van's oil cooling circuits from that era differ from trucks and Tahoes.

Bought a PMD relocation kit (and backup PMD for the glove box) from him. Wish me luck on my cross-country and back return home with the new-to-me 6.5l diesel, my first ever. Van has 24,394 original miles on it. Hoping it will prove to be a keeper.

Ed

[Ziabeam]

Update;
Seller (1,300 miles away) crawled under the van, and confirmed the two oil cooler line part numbers matched GM part numbers, yet saw no third line. Asked him to confirm both lines went directly from oil cooler to the block, without entering the radiator. He said "yes, straight from radiator to the block". ...???... Hmmm. "So there's NO oil cooler, or third line?" I asked. Nope.

Discussed this with Leroy. Turns out any oil cooler found on a 1994-1996 G30 van that has one line to the block, a second line into the radiator, and third line from radiator back to block, is likely an aftermarket configuration, ass a means of ADDING an external oil cooler.

That's my suspicion.
I will update here if I learn anything to the contrary.

Moving ahead, hopefully we'll come up with stainless braided Teflon cored line options for the G30 van factory setup through Leroy's Diesel. Maybe even an option that adds his external cooler, with a third line, as an option? (from block to radiator-out to added cooler-back to block)... only the first line matching the OEM routed "upper-line"

Would also be correct for any 6.5L equipped 1994-1996 G20/G30/G2500/G3500

[More Power]

Other than the vans, apparently, all 6.5L diesels used a separate oil/air engine oil cooler, while the 6.2L diesels from the 1980s used an "in-radiator" heat exchanger. In either case, the factory installation was just a single cooler.

Not sure why you'd need more cooling than one of the two mentioned factory installations, unless maybe your vehicle was being used to tow heavy in the southwest. Back when the 6.5 was more prevalent a lot of effort by the aftermarket companies was invested in products that promised to improve 6.5L engine cooling. More engine oil cooling was a part of that. Can't disagree with the premise. But, most owners were served well enough with just the factory cooler.

Here are a couple of ad images from some time ago... Their web site is https://www.dieselservices.com . Don't know if they still offer this, but it does indicate what's possible for the do-it-yourselfer. We did a full installation/product review for this product back in 2005.

https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=7693&d=1722622487



https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=7694&d=1722622487

[Ziabeam]

That appears to be the case. I tried to update with new findings last night and this morning, neither reply is visible yet, pending administrative review I believe. In summary, discovered any oil cooler on a G30 van is likely aftermarket or optional. Meaning the "third line" is the exception rather than the rule. I also let Leroy know what I discovered.
Thank you for the information. Very much appreciated!

[More Power]

All but one of the forums here at TDP are open to posting by anyone registered and logged in.

The one forum exception was originally intended to be a repository for the best threads.

[JohnC]

from block to radiator-out to added cooler-back to block
Sounds like a transmission cooler setup. (Replace "block" with "transmission").