Weather wise it wasnt freezing out, coolant is 50/50, either xerox g05 or generic green stuff cant quite remember

This happened to me once with my 62 fintail.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

One last thing to add, although with the amount i have driven btwn overheats, in winter and summer i dont think this is it, im not running a fan shroud, and i had to cut a half inch or inch off the metal bladed fan to keep it from hitting a crossmember. I did it carefully and made sure it was even. Im also pretty sure the fan clutch is functioning normally

Hmm no shroud and trimmed fan may be a problem. No expert on mechanical but I know there are some exponents with a 3 in the equations (to the third power) for this stuff. Meaning that any reduction of the fan material has great effect on the outcome.

I want to say one of the forum members (tjts1?) fitted an electric fan from a Prius in his MB diesel. Not sure if it was an OM60x series or OM61x series engine but it appeared to be an easy fitup. Of course you have to make sure you have enough electrical capacity to run it.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Ya, ive been thinking more on this in the past few days. I may try and swap the mechanical fan for an electric unit at some point soon. Im still at a loss for how it would be overheating so quickly on a "cold" engine though. Because once im up to operating temp i seem to be able to hit any hill, at any speed and not overheat.

I have an electric fan on my swap, and drove for a couple years not knowing I had a failed fan controller.

Never had a problem at all in normal driving, even when warm out. It would only heat up while crawling around logging roads, in four way low, while firewooding. Slow speed, high output. I added a manual fan switch to kick it on whenever I wanted. Eventually I decided to troubleshoot. Sat there and let it idle in the driveway, watching the temperature gauge and waiting for the fan to kick on. It never did. I replaced what needed replacing and it works perfectly again, but I'd driven the truck for a long time and just never knew, because the issue so seldom came up.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

Woah, thanx that is super helpful... sounds veeery similar to my problem. Im really gonna kick myself if all the truck has needed was a dif fan set up n i let it sit for soo long! Ill still see if i need an offset woodruff key n maybe adj ip timing, and plumb in the egt and boost gauge so i can see whats going on. Thanx for all the replies! Also, i may start a new thread about a possible vac pump delete, i recently came across one in a junkyard that ran off the alternator

Best of luck!

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

I have a W126 large front electric fan as my only source of cooling, the mechanical fan is removed. An AFCO 85287 195-on 185-off switch mounted in the block side thermostat housing controls the relay. In the cool months (Sep-Apr) the fan only kicks on if I'm sitting in traffic a long time. Summer months it switches on somewhat more frequently under 60mph. *My AC system is removed



Really, the mechanical fan is overkill for these engines if they are running right. Acceleration improved very noticeably from removing it and economy went from 23mpg yearly average to 26mpg, I even hit lower 30's when I'm in the mountains. I still keep the fan around for if we ever have a hard heatwave or I plan on going to Arizona/NM/Texas/SoCal in the summer.

Well, finally ordering stuff. Im gonna have to pull the turbo, or the manifolds again to install pyrometer. Im about to order stuff for the elec fan install, im opting towards a sending unit from the thermostat housing, anyone know of one that would thread in to the (i believe) 14x1.5 hole? Also, what temp range unit do i want? Ie 185 f on, 170 off?

Have you had someone who knows how check the injection timing yet? If this is the problem it will likely solve all the other problems. I don't think you should have a problem from trimming a half inch off the fan or running without a shroud if it is nice and close to the rad.

Early in the thread you mentioned the po had "adjusted" the timing. That was a red flag for me.

The engine has an iron block and head and is not known for being prone to cracking or leaking head gaskets, though around 300K miles the turbo engines tend to get head gaskets leaking.

Is the rad from the same car as the engine? Was it running fine before the swap? Does it idle smoothly?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Hi, in my earlier post i had meant that as far i know the timing was stock, unless a previous owner messed had with it. It idles and runs great, but it is a lil smokey at idle, like too much fuel. The radiator is from summit and is recommended by doomsday diesel who makes the adaptor plates for these swaps, he has used them in many vehicles. I just ordered offset woodruff keys in 3 sizes, im going to use a dial indicator/2mm method to check chain stretch to figure out which degree key to use, then ill do the drip test to re set injection timing. I was gonna go ahead n switch to an elec fan setup n a shroud from the junkyard, but if i can keep the mechanical fan i suppose i will. I can try and post a picture of the fan and radiator set up after the wknd

Update, blast from the past! Was gonna start my own thread but figured the op never came back n most of my backstory was already here. So i ended up putting in an offset woodruff key to even out chain stretch, added an inline filler neck in my upper radiator hose, double checked my thermostat on the stove, hooked up a pyrometer and boost gauge, in addition to coolant temp and oil pressure, performed a compression test (340-350), and a cooling system pressure test. Finally filled it back up w coolant thru the heater core hose into block and my new filler T in the high spot on the upper hose as well as my pressure tank, put the front on ramps n fired it up for first time in at least a year. Started right up in freezing temps! I still need to check the injection timing, but it seems less hazy/smokey once it warms up than it used to be. Havent taken it out on the pavement,but rolled around in 4x4 on our road n it hasnt got hotter than 180° f. Was seeing egt's highest of 450, and boost went up to 8 or so mashing the pedal a bit in second gear. Anyways, i dont trust that its fixed yet,but fingers crossed. Heres a few photos. Cant wait to build a damn shop so i can do all this inside!

Sounds like a great build. I don't see the photos.

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1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660

Photos wont load for some reason. I overheated it again, at this point im almost convinced that the head cracked again, or there is a sliiight leak in the headgasket that slowly puts air into the cooling system, and once the air pocket gets big enough it keeps the thermostat from opening and overheats. I may try re torquing the head bolts before i pull it apart later this summer. Has anyone had luck re torquing a head?