240D too Cool..check my theory?

[bennett]

I posted earlier about my 81 240d running cold even in the summer. Now it barley makes it up to 60* after a long haul.
I put in a new mb T-stat and run a 50/50 mixture of coolant. I have checked the engine temps/ head temps with my infared heat gun and she does run cool..around 150* at best. My gauge appears to be fine.
btw.. I did put in a new bosch water pump a few weeks ago.. had a small drip from teh weep hole...................so my question is....

should I run cardboard in front of the radiator ?.........or
should I remove the fan and and fan shroud until spring ( and watch teh gauge) when temps get above 65* ambient?

EDITED: ALL THREE THREADS ARE NOW COMBINED INTO THIS THREAD

[DieselJim]

Could the viscous fan clutch be stuck? To much airflow will make over efficient cooling.

[t walgamuth]

fan.

yes you may need some cardboard in cold weather. be careful with it though. on the highway you may overheat. start with a small piece.

tom w

[DieselJim]

I personally wouldn't panic about it running that temp. Give it a good italian tune up occasionally I would also see if you can get an after market thermo that runs a little hotter if you are really concerned.

Are you sure the stat is working and installed correctly (not backwards)? Can you feel hot coolant circulating to the radiator when the temp is less than 80C? If so, I would recheck the stat. You shouldn't need to block the radiator to run at the correct temp.

[BluEyes]

Originally Posted by DieselJim

I personally wouldn't panic about it running that temp.

I dunno about a 240D, but my FSM states the minimum operating range for my 220D is 70*c, not 60*c.
Not getting up to full operating temp is not a good thing. You need the heat to get any condensation out of the oil, and for all the running tolerances to get to proper spec. The engine will wear faster and make less power when cold.
I definately would NOT do an italian tuneup unless the engine had been up to full operating temp for some time.

If you go to www.********.com, they have thermostats listed for your vehicle up to 195*F.
If it is interchangable, they also list Behr brand 87*c thermostat kits ('stat and o-ring) for my 220D.

Since you have one of those nifty temp guns (I'm jealous) you could use it to check when the thermostat opens. If you read hot coolant starting to enter the radiator hose when the engine is still pretty cold then you probably have a bad thermostat.

[bennett]

No clutch fan on my 240... direct drive

[bennett]

My 81 240D is too cool .... I have done everything but pull the fan and shroud ( that's next). I cannot get this car up to temp no matter what.
I put a block heater in last night and it makes the startup easy and a faint bit of warmth can be felt very soon after takeoff. Glo plugs seem to be OK as I asked in another post.
Even in the summer I had difficulty hitting full 80*c on a hot day.
What I have done...
New bosch water pump ( weep hole was leaking)
Bosch 80* thermostat and in correctly
I have cardboard and taped off the entire front of the radiator and this made very little change.
Head temps with Infared thermomoter reads 130 at best in these cold temps ( 20*) I am at 4500' elevation and low 20s at night and 30s in daytime.
no restrictions in the vents etc.. fan blows awsome.
Dash Temp gauge reads 50*c and goes no higher even with cardboard.
Should I pull the fan and shroud?.... will this really help?

Something is not right, my 240D was running at 80C today within 5 minutes (with about 20-25F outside temperature). When the engine is as warm as it gets, can you feel hot/warm coolant going to the radiator? The radiator and the upper hose should stay cold until the thermostat opens at 80C. If you are getting flow to the radiator at less than 80C it pretty much has to be a problem with the thermostat opening too soon. If the thermostat is working correctly, blocking the radiator, removing the fan, etc. should no make any difference anyway. I would be tempted to replace the thermostat again (with an 80C OEM) just to make sure. I just can't think of anything else that would cause this. Anyone?

[kmaysob]

have the cooling system and rad. cap pressure tested. if the system cant pressurize it wont heat up right

[bennett]

Are the German motorad thermostats the "fail open" type?

when doing the block heater last night I took the thermostat out and it looked fine in the closed position. I figured if it failed it would fail open causing teh motor to run too cool....

[barry123400]

Is there a possibility that your temerature gauge or sender is out of calabration? Do you have a warm heater? Can you get your hands on a infared temerature probe for a few minutes to check block temp when warm? Probably above does not apply as you mention little cabin heat. To find out if constant circulation is a problem carfully clamp one of the rad hoses using a couple of pieces of wood and a wood clamp to eliminate damage and see if it heats up. Of couirse remove or really loosen up the waterpump belt as you now have no coolant bypass circuit. If it does heat up than somehow or other the coolant is getting around or through the thermostat when it should not be. I do not think any other possibilities exist really other than above. Remember some mention that should be in archives about corrosion in thermostat neck area but thought problem caused was overheating. Would not hurt to pull themostat and put in a pan of water with a thermometer to see what temperature it opens at. It is possible to get a bad new one. If car is the same though it is a long shot but should be checked .Have a look for any major corrosion in area perhaps letting coolant get around the thermostat when your in there. A really long shot and impossible on most waterpump designs anyways is the impellor on the pump backwards. The effects produced if this where so are unknown to me but just verify flow direction is right as you are probably getting exasperated by now mind the cold air from a poor heater.

[bennett]

As a few have read and helped... summary... I just cannot produce any heat out of the motor over 130*F
Long story short I changed and pretty much tried everything but parked it till spring.

I have a new theory on what the problem might be...?

I always felt a little low on power compared to my buddies 240d so I advanced the injection a little and got what I thought was significant increase. Still not as fast as his car but much better for me. I used the bubble method ( blow in the tube) tpo what I felt was to spec.
81 240D 130k miles , great compression, well taken care of car by po. Always serviced and valve adjust done recently.

My question..

could the IP timing be off so much that I am losing heat and power thru compression or exhaust stroke as to not have the complete cumbustion at the right timing? ... hence the power goes out the exhaust .. does this make sense to anyone?


thanks

bennett

[coachgeo]

Could you have a bad temp gauge or sender? And yes.. IMHO based on my small undersanding of diesels if you have poor combustion then an engine would run cooler. Good cumbustion produces more heat.

Try this idea. Use a sensor to measure combustion temps. Adjust timing till you get the highest temps. Some say you already have sensors.... "your glow plugs" More on that topic here:

http://biodiesel.infopop.cc/groupee/forums/a/tpc/f/159605551/m/1071029711/r/3361009911#3361009911

[DieselJim]

If you are running low power try adjusting the valves and run diesel purge.

If that doesn't work pull the injectors and if worn replace them with rebuilds.

Check the IP last.