350SD Running cool, but is it too cool? - Page 2 - PeachParts Mercedes-Benz Forum

Blevinsax · #16 11-01-2006, 10:09 PM

Quote:

Originally Posted by Brian Carlton

My vote is for #3.

#3 says that you should get a non-contacting thermometer and shoot the cylinder head to see what the temp. actually is.

I just won an auction for this infrared thermometer on eBay:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=003&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=130041060587&rd=1

How did I do?

Brian Carlton · #17 11-01-2006, 10:14 PM

Quote:

Originally Posted by Blevinsax

I just won an auction for this infrared thermometer on eBay:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=003&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=130041060587&rd=1

How did I do?

You did excellent.

Decent unit at about 1/2 price.

Blevinsax · #18 11-09-2006, 04:34 AM

Quote:

Originally Posted by Brian Carlton

You did excellent.

Decent unit at about 1/2 price.

Cool - I just got the infrared thermometer in the mail the day before yesterday and boy is it fun... I've checked the temperature of nearly everything around the house, including the cat's butt (84F

)!!!

I have also pointed the thing around all over the engine, and I've seen several different readings - nothing extreme, but I would like to know exactly where I should take temperature readings to best gauge engine temperature. Please bear in mind my self-admitted inexperience with this motor and this car, so please point me in the right direction...

Thanks!

Ara T. · #19 11-09-2006, 06:45 AM

Im not sure how long it should take to get the coolant to operating temp, but my 300D prolly takes 15-20 minutes. I'll time it tomorrow with my new Bulova. Depends on how many stop lights I hit of course.

gsxr · #20 11-09-2006, 11:50 AM

Uh, how about shooting the new IR thermometer at the coolant temp sensor? Did you ever just replace the silly thing, as I mentioned earlier? Ten bucks for the sensor would have been cheaper than the new tool, and I've personally seen this EXACT sensor fail in such a way that it reads 10-20 degrees lower than actual temp. I replace them on principle now when I buy a new diesel.

Ara, the car should reach operating temp within 5 minutes of driving. If it's taking 15-20 minutes, something isn't right, unless you're in Alaska in January. Don't let it sit & idle, start it up and drive away within 30 seconds or so.

Blevinsax · #21 11-09-2006, 12:08 PM

Quote:

Originally Posted by gsxr

...how about shooting the new IR thermometer at the coolant temp sensor...

Hi Gsxr - hey, help me find the darn thing and I'll happily point my new thermometer at it. Again, I apologize for my lack of specific knowledge about these things - I'm a quick learner, though, so please help me and I'll be very grateful (and I won't ask again!)

I have not replaced the sensor yet - I'll certainly do that if I can confirm that it is bad.

I remember when I had Brian's EGR testing kit installed it was mentioned here that I might see lower engine temps since there are no hot exhaust vapors going back into the intake. (Assuming my thermostat and sensor are not defective - a big IF) Could that be contributing to the lower running temperatures?

It cetainly would be nice to have the car up to 80C within 5 minutes as you mention Gsxr! Right now the car doesn't seem to take too long to warm up now - it still takes about 15-20 minutes to get up to 80C, but it is up to 75C within about 10 minutes. Getting to 80C would help significantly with my WVO heat and would allow me to burn less petrodiesel and more (free) WVO.

gsxr · #22 11-09-2006, 12:15 PM

LOL... no problemo. ;-) The sensor is on the side of the cylinder head, approximately below the #2 injector, behind the injection pump. On your car, I believe it has a 2-prong connector (one for the dash temp gauge, a second for the glow plug relay afterglow function). I retrofitted the afterglow setup to my 1987 model, see photo below... you should have the same sensor that's in my photo. My bad on the price, $10 is for the old single-prong sensor. The one in the photo (008-542-56-17) is a little spendier at about $30.

:-)

Blevinsax · #23 11-09-2006, 08:19 PM

Quote:

Originally Posted by gsxr

Uh, how about shooting the new IR thermometer at the coolant temp sensor? Did you ever just replace the silly thing, as I mentioned earlier? Ten bucks for the sensor would have been cheaper than the new tool, and I've personally seen this EXACT sensor fail in such a way that it reads 10-20 degrees lower than actual temp. I replace them on principle now when I buy a new diesel.

Aha! I just found AND checked the coolant temp sensor and it is dead on accurate with my gauge. It seems to be functioning properly.

Quote:

Originally Posted by gsxr

Ara, the car should reach operating temp within 5 minutes of driving. If it's taking 15-20 minutes, something isn't right, unless you're in Alaska in January. Don't let it sit & idle, start it up and drive away within 30 seconds or so.

Is this a general concensus? I've been told by my VW mechanic (granted he is NOT an MB specialist NOR a diesel specialist as some of you folks here clearly ARE) that these cars take significantly longer to warm up than a TDI which warms up in about 5-10 minutes...

So, how long should I realistically expect it to take the 350SD to reach 80C (or thereabouts) at normal ambient temperatures?

t walgamuth · #24 11-09-2006, 11:20 PM

5-10 minutes.

tom w

Brian Carlton · #25 11-09-2006, 11:35 PM

Quote:

Originally Posted by Blevinsax

So, how long should I realistically expect it to take the 350SD to reach 80C (or thereabouts) at normal ambient temperatures?

Well, five minutes is a bit optimistic. I doubt it will make it.

10 minutes is realistic. Any more time than this and the thermostat is probably opening a bit early.

gsxr · #26 11-10-2006, 11:37 AM

On the way to work this morning I got some numbers for y'all to chew on. Car is a 1987 300D, parked in my garage overnight. Ambient temp of the car in the garage was 55°F. Outside ambient temp was 30°F. I started the car, it took about 1 minute to back out of the driveway and drive slowly through my development to the main road. Once on the main road, I accelerate to 60mph and set the cruise on 60. It's a flat road btw, no hills. Here's the times to reach the specified temperature:

80°C - 3 minutes
85°C - 4 minutes
90°C - 10 minutes

Temp didn't go above 90°C, and settled in the 85-90° range. BTW, the heater was on max the whole time. I've got Mobil-1 in the crankcase and Water Wetter in the coolant. It warms up a little faster in summertime when temps are above freezing, lol!

Blevinsax · #27 11-12-2006, 05:54 PM

Okay - I'm ready to order a new thermostat as I am thoroughly convinced that mine is not functioning properly. I looked it up here on MercedesShop and wanted to make sure this is the right/best brand - Wahler?

If someone here would please confirm that this is the part I should order, I will place the order tomorrow. (See below or attached pic)

G4001-49781
Thermostat Kit
Wahler
IN STOCK
$25.00
$24.50

Thank you!

gsxr · #28 11-12-2006, 07:21 PM

Wait - I thought you already have a new t-stat in there. Are you changing it again, to see if the previous new one was defective...?

Blevinsax · #29 11-12-2006, 08:54 PM

Quote:

Originally Posted by gsxr

Wait - I thought you already have a new t-stat in there. Are you changing it again, to see if the previous new one was defective...?

Nope, I checked the receipts and work orders from the work I had done earlier this summer and no new t-stat was installed. Didn't pay for it either - otherwise I'd be pretty pissed!

Is the one from MercedesShop the right one?

Blevinsax · #30 11-28-2006, 02:15 AM

I had the new thermostat installed today as well as a VegTherm Mega and now everything is looking A-okay! Temp gauge is up to 80C within 5 minutes, and the VegTherm is heating the oil nice & hot - I'll check the actual temps soon. Immediately I noticed the exhaust no longer smells much like burgers-on-the-grill and more like a hot griddle. I now see less smoke and runs very smooth most of the time.

I think running much hotter oil will likely expose my worn injectors - I noticed it bouncing a little today after I had been driving a little while - I gave it a mini-ITU and it cleared up, but came back after a little more driving. So, new injectors are next on the list!

I'd like to get a set from Colorado Biodiesel, but I cannot get them to answer the phone, return a call, or return an email. I could get a set of Bosio nozzles and have mine rebuilt, but I priced that here at a diesel shop and their price was ridiculous. Anyway, that will be something I'll get into perhaps after Christmas!

Thanks to everybody for all the help in this thread!