300Tdi Running a bit hot

javelinadave

Administrator
Staff member
Here is what I know and could use a bit of help.
The timing belt was done by a shop about a year and a half ago.
It has a 191 degree thermostat and runs about 198 on flat roads and climbs to 208ish up hill or with the a/c on.
The water temp gauge is accurate per VDO specs
The thermostat is functioning fine (tested it in a pot of water)
Water pump is new
New fan VC
The radiator top hose is showing 175ish degrees

Could it be the timing? If so do I need to advance or retard it?
I'm open for any ideas you may have.
 
Do you have an IR gun, if not but one that has a +- rating of 2 degrees F,
(+- 5 won't cut it).
Also, did you run a 14GA wire from the sensor to the gauge, according to Ian in Vegas, this is necessary.
Take your temp reading on the engine right by the sensor location.
You can also use the gun to measure the temp in your boiling water to see what the actual opening point is.

Here's one that is +- 1.5 degrees
http://www.homedepot.com/p/PRO-SERI...th-Laser-Sighting-12-1-Spot-THERMNC/204262824
 

javelinadave

Administrator
Staff member
I'm using the factory wiring but when I called up VDO tech support and they had me read the resistance of the sender and determined that the gauge is reading correctly.
My laser temp reader at the sender shows a few degrees cooler than what the gauge is saying.
 
I am battling a similar issue with my truck but it is running a bit cooler then yours (195/203-205ish). My suspicion is there is just some gunk build up in the system. My radiator, water pump, intercooler, headgasket, hoses, fan clutch are all new. VDO water temp gauge using factory sensor wire with a independent ground to the firewall

I am doing a SERIOUS flushing of the engine this weekend using what Napalm00 suggested on the other forum in addition to installing electric fan.

Hopefully it works because I am at like $75 in chemicals and coolant

I recently flushed my 200tdi and it made an amazing difference.

Exact steps I took (overkill prob) as follows:
  • drain coolant from lower rad hose and block
  • Block drain is near the oil drain pipe for the turbo connection on the block
  • reconnect lower hose but leave block drain open
  • open top of rad filling plug
  • spray garden hose into filler on rad and overflow canister until it runs out of the block drain
  • flush like this for a few min with cool water
  • refit block drain
  • fill with water and a tub of sulfamic acid (premixed)
  • Warm up truck to operating temp and let idle for 20 or so min
  • Drain above mixture
  • fill with water and a tub of oxalic acid (premixed)
  • Warm up truck to operating temp and let idle for 20 or so min
  • Drain above mixture
  • Flush again with garden hose
  • Fill with water and a mixture of washing Soda (not baking soda)
  • Warm up truck to operating temp and let idle for 20 or so min
  • Drain above mixture
  • Fill with garden hose again
  • remove block drain then lower rad hose
  • refit block drain and rad hose
  • mix you choice of extended life coolant (I use standard green w/o silicates) and bottled distilled water
  • Add bottle of anti cavitation additive for diesels
  • Fill and bleed system


This took me about 2 hours to do on a huge ass tarp, Had about 4 five gallon buckets of waste water to be dropped off for recycling


System is now fully free of rust oil, sludge and mud. Coolant is perfect mixture and bright green.

As long as you dont let the acids sit in the system for an extended period it is safe for the mixed metal engines we have. I adapted this from a post on H.A.M.B, it worked flawlessly...system runs cooler, warms up faster and the heat works better. Its a great time to replace any sensors and hoses FYI

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/Arm-Hammer-Su...s=washing+soda
 

Dan kemper

0
Callsign: KK6ECF
the vdo gauge will read high if not independently grounded. If temps same with iR gun then you have some work to do.
 

javelinadave

Administrator
Staff member
I'll try rewiring it tomorrow with 14 gauge wire. After that I'll try re-timing the engine and a 180 degree t-stat. I'm skeptical about etching the cooling system since I have an brand new Allisport aluminum radiator and tank.
 
I'll try rewiring it tomorrow with 14 gauge wire. After that I'll try re-timing the engine and a 180 degree t-stat. I'm skeptical about etching the cooling system since I have an brand new Allisport aluminum radiator and tank.

Curious to see how the 14 gauge sensor wire works out. I am hopeful but skeptical that will do anything.

I have heard if the timing is retarded it can cause the truck to run warmer, and be down on power. Apparently without setting the fine adjustment with a dial gauge to set it you never really know... This is in addition to just getting the flywheel and timing pin marks lined up

Just because the rad is new doesn't mean there isn't gunk in the block/heater core, and also now in your new radiator...
 

Uncle Douglas

0
Callsign: delete
Dave if your thermostat doesn't even open until 191 degree's to allow coolant into the radiator to get cooled down then your temps are quite normal- especially for Az. Diesels run more efficiently/better around 200-205. If you swap to a 180 degree tstat then coolant will be allowed into the radiator earlier and that should get you where you want to be.While water boils @ 212 @ sea level, our cooling systems do not because of the higher boiling point of antifreeze and then the fact that its under pressure so cant boil. A RED zone for these engines should be 225 degree's and 235-240 overheating.
 
Dave if your thermostat doesn't even open until 191 degree's to allow coolant into the radiator to get cooled down then your temps are quite normal- especially for Az. Diesels run more efficiently/better around 200-205. If you swap to a 180 degree tstat then coolant will be allowed into the radiator earlier and that should get you where you want to be.While water boils @ 212 @ sea level, our cooling systems do not because of the higher boiling point of antifreeze and then the fact that its under pressure so cant boil. A RED zone for these engines should be 225 degree's and 235-240 overheating.

The viscous fan clutch engages completely at what temp? 205? 210?
 
Just because the rad is new doesn't mean there isn't gunk in the block/heater core, and also now in your new radiator...
The block and heater core can hide lots of gunk for sure.
I lost a freeze plug last fall and even after draining and running water through the system it was still very dirty. I used the commercially available stuff twice and it was still discolored but I needed to get the truck running so I just plugged the hole and moved on. I plan on this summer doing a better job of flushing it out and replacing all the freeze plugs.
 

Uncle Douglas

0
Callsign: delete
The viscous fan clutch engages completely at what temp? 205? 210?
In a perfect world but depends on brand etc. That's a bit of a misnomer because the fan clutch gets its heat from conductivity from the water pump impeller shaft and then through the hub, pulley, etc. Lots of surface area, and then the heat sink on the clutch itself
 

Uncle Douglas

0
Callsign: delete
Once truly up to temp the test is to take a rolled up news paper and try to stop it with resistance. You shouldn't be able to stop it
 

javelinadave

Administrator
Staff member
No difference with the 14 gauge wire.
Guess a 180 degree t-stat is the next step.

Currently 85 degrees out on the test drive.
 

Attachments

  • IMG_8772.jpg
    IMG_8772.jpg
    177.6 KB · Views: 237
FYI, All this talk of theromstat temps is funny, if you fit a 190 (88C) Stat that is the opening temp, the enginner I talked to at Stant says the fully open temp is 20 deg F higher. So at the fully open temp is when the by-pass is covered (closed) allowing full flow to the rad. Which is in the realm of the most efficient temps for a diesel. What UD said earlier.
 
Guess a 180 degree t-stat is the next step

Why don't you check your lift pump timing first?
--------

I don't get how many "experts" of these trucks claim they are over cooled and don't need a fan this and that. So many claim there trucks run 189 and the gauge never budges. Yet here you are with a big ass aftermarket rad and fan and have a creeping gauge.

I don't like watching my water temp gauge creep up and down.
 
Top