|
|
|
#1
|
|||
|
|||
85 300d overheats
My car recently is having overheating problems.
Car was driven on freeway when the temp needle started climbing. Before this the temp showed normal or sometimes very low. I noticed during the overheating that the hot air is not coming out of the vents. But at times when the hot air does come out, the temp needle returns to normal. I can also hear a wirling/grinding sound from the dash in front of the driver. It seems like it's a clogged water hose? or some other device that's not working properly? Is it the mono-valve? Any insight is appreciated! Car is a 1985 300d california edition. Thermostat changed a few months ago. |
#2
|
||||
|
||||
Still check the T Stat. They are known to be bad out of the box. I need to replace mine again as well. When the weather gets cool like it has, the temp will go to 100 and stay during highway runs then drop at idle. During the summer, the engine temp stayed at 90. I have the 90 degree t-stat. I want an 80 degree fail safe.\
I'm thinking the t-stat is too sensative and is closing when the cooler water gets to it.
__________________
RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
#3
|
|||
|
|||
I second the thermostat. I can't think of anything else that can cause an overheat condition so rapidly other than a water pump failing catastrophically which pretty much doesn't happen on our cars. I have seen many new thermostats bad out of the box as well.
__________________
1984 300D, 246k, veggie, sold 1982 300SD 301k |
#4
|
||||
|
||||
Quote:
Could the cool airflow chill the thermostat housing enough to prevent it from warming enough to open until water is 100C? A small hole drilled in the top of the thermostat might help with both of these problems.
__________________
'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png Broadband: more lies faster. |
#5
|
||||
|
||||
First thought with gurgling noise is air in the cooling system. So check recovery cap, make sure it holds proper pressure. Pressure test system for any leaks. Test hot then with pressure tester on under pressure overnight to ck for leaks when only cold. From what you describe, the car is running hotter than normal not overheating. How high does the temp needle go? If no leaks found, and cap passes pressure test, then I would suspect thermal fan clutch.
__________________
81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE. |
#6
|
|||
|
|||
Wow, thanks for all the quick responses. I have parked the car for now and am using my 87 300sdl.
A little more information and history: When I first got the car 7+ months ago, the temp needle stayed at 0 degrees. So I changed out the thermostat; after which it started reading operating temp of around 80 degree C. I noticed that the old t-stat had a hole in it though and the new one didn't. Anyways, the car runs along well all this time, but it did over heat once or twice before, but when that happened, I just added more coolant and it ran fine again. When it overheats, there is boil over...steam hissing from the engine area and I smell coolant in the passenger area. Needless to say I keep a good eye on the temp needle and top off the coolant all the time. It feels to me that something is clogging the coolant to the engine and heater core? during the overheating episode since I turn on the heater and only cold air comes out. When hot air does blow out, the temp needle drops to normal right away. I'll try to do a flush and check out the hoses and such this weekend. Quote:
|
#7
|
||||
|
||||
This indicates that the system is almost working. Your statement says that extracting a little bit of heat from the coolant (with the passenger compartment heater core) makes the temp gauge happy. Unless the radiator core is partially clogged (internally or externally), the thermostat would indeed be the next thing to try. Without spending any money you could remove the thermostat and run the car without for a little while, see how hot it gets.
__________________
"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#8
|
|||
|
|||
The reason I think something is clogging or malfunctioning is this:
I'd be driving along and everything is normal...heat blows out of the vents if I turn it on. Then bam, no heat out of the vents, cold air, and the temp needle rises. If it doesn't climb too high, I fiddle around with the climate control and sometimes it'd kick in hot air again and when this happens, the needle immediately goes to normal. I also hear some whirling/grinding sound in the dash area right in front of me. Then bam the needle rises again. This happens on either city streets or on the freeway. It only started happening when I was doing 80+ mph on the freeway and I normally only drive 60-70. I do notice that the car runs hotter climbing hills and it does struggle up the hill. This is a turbo 300d. |
#9
|
||||
|
||||
Quote:
Quote:
__________________
'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png Broadband: more lies faster. |
#10
|
||||
|
||||
I'm guessing you have air in the system from changing the T stat. How did you bleed the system when you did the T stat?
__________________
1985 Euro 240D 5 spd 140K 1979 240D 5 spd, 40K on engine rebuild 1994 Dodge/Cummins, 5 spd, 121K 1964 Allice Chalmers D15 tractor 2014 Kubota L3800 tractor 1964 VW bug "Lifes too short to drive a boring car" |
#11
|
|||
|
|||
Woo! I got the 300d running again. Here's what I did:
Flush out the old coolant. I didn't use any special flushing kit. I disconnected the coolant line to the engine and the heater, hooked up a water hose, open the radiator drain and let the water flow through. The water coming out was quite murky. I also ran water through just the radiator to flush out any gunk. I also removed and cleaned the reservoir and replaced the thermostat. Then I ran the car on just the water for awhile. It never overheated and the heater blew hot. After this I did the same flushing, blew out as much water as I could with air and fill with a mix of 50/50 coolant and distilled water. I ran around for about 10-15 minutes and still no overheating. I ran 30 miles/35 mins to work today and it only went up to about 60 degrees. In the process of flushing out the coolant and messing around with flushing the radiator I managed to break the plastic hose connector to reservoir off the radiator. I noticed after removing more of the plastic that there's a threated metal part on it. Went to the hardware store and found a screw with a hole in it and threated it back to the metal part and it seems to hold nice and tight! Saved me from having to replace the radiator. yay!
__________________
1987 Mercedes 300sdl, 280k mi (daily driver) 1982 Mercedes 300sd, 205k (occupying driveway) 1985 Mercedes 300d, CA, 148+ mi. 1986 Chevrolet suburban, 50k? or 150k? mi, diesel 1998 BMW 740il, 120k mi (for sale) 1999 Honda CBR900RR, 42k 1997 Jeep Wrangler Sport, 103k miles (sold) |
#12
|
|||
|
|||
Crap. Still got the same overheating problem.
Temp still climbs when hot air is not blowing out of climate control. When hot air does blow out, temp is normal. I can hear this grinding sound from the dash as if something is opening when the hot air does finally blow out. What's behind the dash (right in front of driver)? Is it the heater core plugging up? I can see coolant hoses going from the engine into the cabin. Looks like it's pretty hard to get to the heater core? under the dash. Can I prevent this overheating by completely removing the t-stat or drilling a couple of holes in the t-stat?
__________________
1987 Mercedes 300sdl, 280k mi (daily driver) 1982 Mercedes 300sd, 205k (occupying driveway) 1985 Mercedes 300d, CA, 148+ mi. 1986 Chevrolet suburban, 50k? or 150k? mi, diesel 1998 BMW 740il, 120k mi (for sale) 1999 Honda CBR900RR, 42k 1997 Jeep Wrangler Sport, 103k miles (sold) |
#13
|
||||
|
||||
Quote:
__________________
http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|