Hello I have a om617 in a toyota pick up and have the om617 in it it is out of a 1983 300 td and I have 5.89 gear ratios for my axle and every time I go to the mtns it over heat and the egts get 1600 ish and I have a stock toyota radiotor now with an electric fan and I also have an aluminum 3 core radiator that I haven't put in yet because my adapter plate got all messed up so I need to get a new one so right now the truck doesn't run but I am wondering if it's going to be worth it to buy another adapter plate and try the radiator out or do you guys think I should just do a different motor? everything is fine when I run it in town it only does it going up to the mtns it also pressure tested the radiotor to see if it was a cracked head and it is fine.

here is a picture of the truck let me know what you guys think thanks for your time.

for some reason I can't put a picture on

these engines are better at taking abuse than the 603 is as far as overheating. but i might seriously think that by the time you hit 1600 on your EGT damage has already been done. as far as correcting the issue i assume you have the pump turned up? high EGT could be bad injectors peeing, retarded timing, damaged prechambers, or damaged/mis-adjusted delivery valves. as far as the overheating goes its probably due to the high EGT's. being an in-direct injection engine some of the combustion heat is absorbed by the head so if your combustion temps go up so does the engine heat load.

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1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P

yes it does seem like it is a good motor and the pump isn't turned up its stock and everything runs perfect if I drive in town or on the free way it only acts up pulling big hills such as going from 1000ft to 3500-4000 in 30 to 45 mins so it's up hill but it takes a long time to get there

and I also have my egts Guage right off the the exhaust manifold and how can I check to see if there is damage do u think I can get a boreascope in there some where?

Is the radiator the same size or larger as the original Mercedes Benz radiator? If not, that's bad.

R-3350 pointed out everything I can think of. If you have low boost your EGTs would be high too.Install a boost gauge.

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3 Row 1988 1995 Toyota Pickup 4Runner 4WD 3 0L V6 Aluminum Radiator | eBay
here is a link to the raditor it's not the exact one but one just like it and I have not tried the aluminum one yet I haven't been able to work on it for about a year cause I had to move and wasn't able to bring it with me but now I wanna get it going again and I think I was running 6-8 psi I believe not 100 percent for sure though

and if it did do damage to the engine wouldn't it be pretty noticeable? cause when it was running it would run just fine in town and stuff

High altitude and high heat are not good partners.... thin air does not carry away as much heat

You can't just fill the radiator and assume that these engines will pump coolant properly. You have to "burp" them to get the air bubbles out so that the pump is fed with solid coolant and doesn't cavitate. Just google "burping an om617" Also look at the cabin heater coolant outlet near the back of the head - just above the oil filter - and make sure that coolant can flow out of it and back to the inlet under the thermostat housing... this improves coolant flow to the head.

There are vacuum devices that will pull a vacuum on your coolant system and then fill it with coolant while getting the air out. Look at "Air Lift"

It is not hard to heat these engines up under full load, but it is hard to get the heat out once they get hot, especially at altitude. You need everything on your side: good radiator, good water pump, good Mercedes-Benz thermostat, decent electric radiator fan (I don't trust the mechanical fan clutch), air bubble free coolant passages, good turbo with good boost (14 psi @ 3000 rpm). An intercooler helps. Water/methanol injection helps.

If all else fails, just downshift and run at higher rpms under reduced load to get as much air as you can through the engine. It also helps to turn on the cabin heat full blast ( I know it's hot out! )...

well I have a hole drilled threw the thermostat and my gearing is so low that I pull 5th gear doing about 50mph so I am not putting a huge load on it and I have a black magic fan that puts like 2 thousand some cfm so it's getting air flow but I am just wondering if that aluminum radiator will make that big of a difference vs the stock one i had in it cause I need to buy another adapter plate for it but I don't wanna keep spending money on it if I can't fix the problem and how about getting my egts down?

First of all, put in a good thermostat. Drilling holes in the thermostat is a mistake. If you're overheating there's another reason.

The number of rows in a radiator tells you nothing about how it will cool, unless you know the size of the tubes and the fin density. There are a lot of replacement aluminum radiators out there from Asian sources which have a multiplicity of tiny tubes and a dense fin structure. This is because people see "three row" or "four row" and think "better". These radiators are often more restrictive than stock radiators, and won't help you one bit.

I think your problem is that stump puller rear axle. Diesels build heat at high revs because that's where they will burn more fuel. Switch to a 3:54 and I think your temps will be fine.

x2 replace the thermostat and report back.

Also, how are your injectors spraying? If they stream things can get weird.

How's your timing/chain stretch?

I never got over 1100*F (pre-turbo) on long heavy pulls

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I actually run under 700*F EGT on a WOR (wide open rack) run under full load for a mile. On the other hand I'm not at all sure my engine is making full power (working on that). I have good compression and have run from 14 to 20 PSI boost pressure.

In other words I don't have a clue on your issue. I do run a conventional thermostat (no idea of the brand) and a 3 core Chevy big truck radiator. My guess is that elevation is not helping your situation and a big radiator never hurts - I'd install that aluminum unit and go back to a regular thermostat.

Dan

i run around 1150 EGT steady at wot doing around a 110 on a 1985 with the 2.88 rear and i have a few things turned up. i didnt even know you could hit 1600 on your EGT from a stock pump. again check your injectors, pump, and timing too. the overheat is from the combustion heat being bled into the head by the pre-chambers running too hot. if your EGT is 1600 after leaving the engine think what the temp in the cylinder is at peak. as for the damage it will start to melt the faces of your pistons can also burn the exhaust valves. its not always catastrophic but the damage can build up over time.

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1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P

I just had another thought (OUCH that hurts!!!).

I worked in instrumentation as part of my dyno work and I know calibration is critical. Get yourself a vessel of ice slurry (a fast food drink cup works great) and set up a hot plate to boil some water. Pull out your EGT probe and drop it in the ice water - should read pretty close to 32*F (0*C). Give it a few minutes to reach the temp and don't forget to correct for your altitude (though there's little effect at 32).

Then drop it in the boiling water and again let it come to temp. Should read 212*F (100C) in a few minutes, again correcting for altitude (atmospheric pressure effects the boiling point considerably). Don't let the probe sit on the bottom of your pan as it will, to some extent, read the heat of the burner and not the water temp. I bent a hunk of wire to hold mine midway in the pot.

In a perfect world you would have about a 1,000*F point as well but that's pretty hard to do and the 2 point cal should tell you if your EGT is in the ballpark or not. It's probably fine but that's something you can cross off the list. When I did mine (Auber) they were pretty darn close.

Dan