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  #31  
Old 06-29-2007, 07:17 AM
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Saw it...

SB,

I don't mean to argue.

I agree that 90 C is a good operating temp. But in my case it is the very low end of the range, without running AC, loading the engine or excessive outside temps.

I am happy that it stays under 100 C now, and I'm comfortable enough to drive the car this way. But, I would be even happier if it ran normally closer to 82-84 C.

I'm using my 85 300TD as a "control". It has always run at say 88-90 C unless under extreme load conditions. Even then I always felt it was running a little bit on the hot side.

BTW, I juts thought I'd throw this extra bit of information in. When it first warms up to say 95 C, if I turn on the defroster I get an immediate drop by ~ 10 C as coolant in the heater core dumps into the rest of the coolant. (Of course this only works once.) I've interpreted that as the coolant having sufficient circulation, am I wrong?

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  #32  
Old 06-29-2007, 08:19 AM
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SB, I certainly understand and agree with what you are saying. however, my car immediately heats up to 105 or so in the morning, when it is still under 70°F outside, and it stays there. the car used to stay around 80C before I found the leak and the bad resivoir cap and leaking radiator. I replaced all that, and the temp started rising. I used a used radiator, new cap 13psi, and flushed and changed to MB coolant. 105 without a/c on when it is under 70°F out, concerns me. and it has been getting upwards of 101ish here lately, I am afraid to run the A/C... so I REALLY hope getting a lower temp thermostat will fix the issues.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #33  
Old 06-29-2007, 10:04 AM
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Join Date: Aug 2006
Location: West Virginia
Posts: 1,268
Arrow Guys, you are missing the point.....

The thermostat does not work as the one in your Ford (or other US vehicle) does......please look at the coolant flow diagrams in the service manual.....

You must run a thermostat.....
The coolant entering the water pump will be at 80*C or whatever T-stat rating....
The coolant starts out around the cylinder liners (jacket water) and works it's way thru the engine gathering up BTU's and increasing in temperature until it passes by the Engine Temperature sensor (in the head) before it exits the head and into the thermostat (mixing valve)......
The thermostat/mixing valve will then modulate the combined coolant (the hot coolant exiting the head and the cool coolant exiting the radiator.....and allow the now 80*C coolant to enter the water pump......and so it goes.....

You must look at the temperature rise across the engine.....a 10*C rise is good......from 80*C to 90*C......

The reason that you get an immediate result from turning on the defroster is....the outlet of the heater core enters the back end of the head via that hose that gets in the way during oil filter servicing....perhaps a full 6 to 8 inches from the Engine temperature sensor.....

so now....if your coolant has been modulated to the proper temperature (lets just use the 80*C)......and you are getting an actual outlet temperature of 90-93*C.....all is working as it should.....

if your coolant is entering the engine at 85*C...then after it makes its trip thru the engine.....it should be about 95-98*C.....still indicating that the engine is in good order....

if your coolant is entering the engine at 80*C and exiting at 95-98*C....then you either have an excess amount of heat within the engine or....most likely, a weak water pump.....

if your coolant is entering the engine at 85*C.....and your thermostat is new (or nearly so) and installed correctly (please refer to the diagram mentioned).....and if it's an OE or OEM T-stat...there is a little arrow on it's rim....this arrow points up.....if this is all correct.....you need to check the condition of your radiator.....

Guys, I am trying to help....you are obviously chasing your tails here......if you don't believe me, check with someone else.....Bill Hunter for instance....

Please Note: if you have excessive scale inside of the engine, that scale will, in fact, decrease the heat transfer from the iron to the coolant......so you could have a hot head and the Engine Temperature sender picking up that temperature thru the threads where it screws into the block....and actually have a lesser temperature of the coolant as it exits the engine....I doubt this because you get the immediate reaction when you run the defroster.....so....why would the coolant be hotter?.....because there is insufficient flow of coolant thru the engine......

get a reading on the coolant as it exits the engine.....and as it exits the radiator.....and on the water pump casing.....then you may have some idea as to where your problem lies....

SB
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #34  
Old 06-29-2007, 10:11 AM
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I was under the impression that the outlet from the heater core was under the thermostat into the water pump. is this not correct? the hose that gets in the way on oil changes should be the HOT outlet from the boiler(engine) to the heater core yes?
anyway, I would be thrilled with 90°C temps.
105 with hardly a load is too much in my opinion.
I will pull the water pump soon. I already have a rebuilt one.
the top hose on the radiator sits at 100C the lower hose sits at 70C I think the block is scale free, and the thermostats are fine, lower may help, but I think it is a water pump issue. when I get mine out, I will take pictures.
thanks for the berating and teaching SB.
we need it sometimes.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #35  
Old 06-29-2007, 10:13 AM
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oh, and just to be sure... the flat disc on the thermostat goes into the engine block yes?
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #36  
Old 06-29-2007, 10:36 AM
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Join Date: Aug 2006
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Posts: 1,268
Sorry...I was mistakem.....

I was mistaken regarding the flow of the heater.....but the rest is as I have stated.....

the little disc part of the t-stat goes into the thermostat housing toward the engine block.....

so then, in Mr. Sherida's case......turning on the defroster increases flow thru the engine.....so it explains why he gets an initial temperature drop....hmmmm.....then why would it then increase again......????

And VS...I think your used radiator may be your problem.......

I wish that I was savvy enough to be able to post a .pdf file here from the service manual.....
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #37  
Old 06-29-2007, 10:50 AM
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Quote:
Originally Posted by Shorebilly View Post
so then, in Mr. Sherida's case......turning on the defroster increases flow thru the engine.....so it explains why he gets an initial temperature drop....hmmmm.....then why would it then increase again......????
funny thing is we are both Mr. Sheridan's...


Quote:
Originally Posted by Shorebilly View Post
And VS...I think your used radiator may be your problem.......
oh, I hope not. I have flushed it well, and the coolant leaving the used radiator is around 70°c quite cool.

Quote:
Originally Posted by Shorebilly View Post
I wish that I was savvy enough to be able to post a .pdf file here from the service manual.....
this is simple in windows, just bring up the page of the pdf you want to post, hit the print screen button, then open ms paint and hit ctrl v then save the picture as a .jpg then either post it here, or upload it to photobucket.com and link it here.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #38  
Old 06-29-2007, 11:00 AM
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Join Date: Aug 2006
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Posts: 1,268
Curious.....!!

Quote:
Originally Posted by Shorebilly View Post
I was mistaken regarding the flow of the heater.....but the rest is as I have stated.....

so then, in Mr. Sherida's case......turning on the defroster increases flow thru the engine.....so it explains why he gets an initial temperature drop....hmmmm.....then why would it then increase again......????

I wish that I was savvy enough to be able to post a .pdf file here from the service manual.....
I just looked at the coolant flow diagram, again.....in Mr. Sherida's case it would seem logical that if he turned on his defroster, it would initially increase flow thru the engine.....forcing cooler coolant from the heater core into the suction of the water pump......this coolant does not pass thru the thermostat.....so all things working as designed.....the thermostat modulates the coolant for 80*C.......when coolant reaches 94*C all flow should be thru the radiator with the by-pass closed by that little disc......

I don't understand exactly how the T-stat is sensing the 80*C of the mixed cooling water........I happen to have my T-stat housing in hand, because I am awaiting the short hose that goes between it and the water pump.....I will think on this.....need to get some stuff done around here today.....will get back when/if I have a profound revelation......

SB
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #39  
Old 06-29-2007, 11:03 AM
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Quote:
Originally Posted by Shorebilly View Post
...why would the coolant be hotter?.....because there is insufficient flow of coolant thru the engine......

get a reading on the coolant as it exits the engine.....and as it exits the radiator.....and on the water pump casing.....then you may have some idea as to where your problem lies....

SB
Your input is definitely appreciated.

I had to read your post several times over, but I've got it now.

What I really need is a non-contact IR thermometer to diagnose the system.

With regards to why the temp drops and reheats when I put on the defroster, I just assumed it was because I'm releasing several liters of "cold" coolant from the heater core into the system (which equilibrates with the rest of the "hot" coolant in a minute or so). The only reason I mentioned it is that it seems to indicate that at least the water pump is still pushing coolant (although maybe inadequately).
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  #40  
Old 06-29-2007, 11:06 AM
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Do I have this right? It seems that both John and Doug, after having citric acid flushed their cooling system, are both experiencing hotter running temps.

Could it be that the citric acid broke up the scale inside the engine into big pieces which are difficult to flush out, settled into low spots in the engine coolant passages, thus creating restriction to coolant flow thus the higher running temps?
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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
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  #41  
Old 06-29-2007, 11:09 AM
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Quote:
Originally Posted by funola View Post
Do I have this right? It seems that both John and Doug, after having citric acid flushed their cooling system, are both experiencing hotter running temps.

Could it be that the citric acid broke up the scale inside the engine into big pieces which are difficult to flush out, settled into low spots in the engine coolant passages, thus creating restriction to coolant flow thus the higher running temps?
No, it was running hot prior to the flush (a bit over 100 C).

In fact it is running about 5-10 C cooler now, and is in a much more acceptable range for my comfort (90-97 C). Its just not as cool as I'd like to see.
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  #42  
Old 06-29-2007, 11:09 AM
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well, I flushed twice, and drained out the block drain plug with TONS of water. so unless the scale is too big to flush out the 14mm drain hole, I don't think that's it.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #43  
Old 06-29-2007, 11:15 AM
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Location: West Virginia
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Gotta go......

Quote:
Originally Posted by vstech View Post
oh, I hope not. I have flushed it well, and the coolant leaving the used radiator is around 70°c quite cool.
70*C = 158*F.......cool???

unfortunately my coolant is drained and the T-stat housing out....so I cannot run my car to get a number for my radiator outlet.....

but I suppose that 70*C would be good, allowing for a mix to acheive 80*C to the engine......

you did say that you could not get any temp amounting to much with the t-stat removed.....

water pump??

I have just changed mine.....because I was beginning to hear a bit of bearing noise.....it still works.....and has some lifetime left....I could send it to you.....

The flow diagram shows a vent on the water pump casing.....will go and look for it later, but don't remember seeing one......

SB

FWIW: as the manual says...run the aux water pump when refilling the coolant......so in theory you should not have any air bubbles in the head......
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #44  
Old 06-29-2007, 11:23 AM
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thanks, I did run the aux pump while refilling. and I filled through the upper hose as well,
temp of water out the radiator is 115/120ish. I guessed at the 70C temp. (man it's nice having an IR non contact thermometer! I guess I could have set it to C to do the measurments...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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