Always at 100* - Page 4 - PeachParts Mercedes-Benz Forum

winmutt · #46 04-01-2009, 10:30 PM

47.2 ohms gauge measured 95ish. I am going to redo the fan clutch next.

If the tstat was in backwards would I get heat?

Oracle12345 · #47 04-01-2009, 11:17 PM

yeah

charmalu · #48 04-02-2009, 02:19 AM

on the left side of the block are two water sensors. one for the temp gauge and the other for the glow plug timer I think. you can swap the wire connectors between the two to see if it is a sensor.

changing the fan clutch won`t make any difference in how hot the engine runs at highway speeds. after30mph or so there is more air coming through the radiator than the fan can pull.

I was having the same problem with the old eng. suddenly started to run hotter. was going to do a citric acid flush, then threw the chain. ended that idea.
replaced with the metric motor eng. and it too ran hoter than I liked, around 100c. changed the sensors, changed the gauge twice, new radiator, t-stat, checked with IR gun and was not hot, was with in acceptable range. changed the t-stat with a 75c and helped some.

Thought the new eng being tight might be some of the problem.

Now I say screw it, and just drive it. got tired of worrying about it

.

place a piece of tape over the gauge, and enjoy the ride.

maybe the low sulpher fuel is the problem. I know before they started messing with the fuel, it ran around 80C. just a thought.

Charlie

tombance · #49 04-02-2009, 05:38 AM

I had plenty of problems with my car overheating a year ago, and in the end it turned out to be the radiator. HOWEVER, in the process of discovering this I replaced my old (Wahle - original I presume) T-stat with a new one from the dealer, and after that my average temperature has always been around 95C instead of 80C. I was initially concerned about this, but as in Winmutt's case it stays at this temp most of the time, only ever going to 100C on long (5 mile) uphill grades.

I'm not the only one who has had this issue. Although I dont have any links, I'm sure I've read about people having the same experience as me before. This leads me to suggest that the new T-stats you get from the dealer are set to open at higher temperatures, probably as a way to improve efficiency and emmissions. I've been running like this for a year and never had a problem, so I would just accept it, and not worry until it starts going ABOVE 100C (i.e abnormal for you).

ImBroke · #50 04-02-2009, 05:48 AM

My 83 likes to run at between 95 and 98. doesn't go higher. I am thirding the ideal of the IR thermometer. Now to find other uses for it..

charmalu · #51 04-02-2009, 09:52 AM

Checking the wife with the IR-Gun to see if she is at proper operating temp to proceed

winmutt · #52 04-02-2009, 11:42 AM

The thing I don't get was the one sustained period of 90+ mph getting me into 85C range. Like it needed burping, but then returned to its previous temp. I have also changed the from the old metal one with good clutch to newer plastic with not so good clutch. Neither had an affect. I am still not convinced there isnt a leak somewhere in the original hoses I had.

vstech · #53 04-02-2009, 12:16 PM

still futzing with this eh? 100C is fine.
odd that at 95mph the temp dropped, unless airflow through the rad was the issue... are you sure the a/c condenser is clear? I got sick of chasing my temp issues, 100C is not a problem with the 617. enjoy.

winmutt · #54 04-02-2009, 12:21 PM

Quote:

Originally Posted by vstech

still futzing with this eh? 100C is fine.
odd that at 95mph the temp dropped, unless airflow through the rad was the issue... are you sure the a/c condenser is clear? I got sick of chasing my temp issues, 100C is not a problem with the 617. enjoy.

Yes but my commute is about to go from 12 miles round trip to 40. From surface streets to stop and go traffic in the US's worst traffic city. With summer temps going REGULARLY into triple digits. I think its more of a leak and less of a flow issue.

winmutt · #55 04-28-2009, 11:00 AM

Again yesterday, 90+mph a cool 85*.

jt20 · #56 04-28-2009, 11:42 AM

I remember reading once that someone opened up their WP and found the pump vanes to be worn away by sediment and such.

just a thought.

winmutt · #57 04-28-2009, 04:45 PM

Its cross my mind as well.

JEBalles · #58 04-28-2009, 04:56 PM

I have a similar issue. My 240 runs at about 89* which if I recall correctly is higher than during the winter, is this normal? I don't remember what it ran at before the winter. It doesn't pass 90* though.

rcounts · #59 04-28-2009, 11:48 PM

Like so many others, mine, with a replacement engine, new t-stat, radiator vanes and AC compressor vanes all cleaned out, new monovalve, etc., etc., etc,. seems to want to run right at or near 100*C. As long as it regulates itself well and doesn't go more than a 5* or so above 100*, then I'm a happy camper.

Internal combustion engines (gas OR diesel) are generally designed to run at optimum efficiency in the 200-220 range. That is why they have pressurized cooling systems and glycol in the coolant - so they can run at or slightly above the boiling temp of plain old water. So at that temp you're getting the best possible efficiency.

I'm thinking that your 90+ mph temp drop may be due to the sheer volume of airflow through the radiator AND engine compartment at high speed. Maybe you've simply got enough airflow going on at that speed to cool everything down below what's "normal" for your engine.

Other than that it seems like the one significant component you really haven't swapped is the gauge. Based on this

Quote:

90C-51 ohm
100C-38 ohm

and this

Quote:

47.2 ohms gauge measured 95ish

it seems that your gauge may be at least a little bit "off"
In theory 44.5 ohms should give a reading of about 95* on the gauge, and 47.2 ohm should read more like 92*-93* on the gauge. Not a huge discrepancy, but maybe part of the issue - especially if the 95-ish you read on the gauge was really more like 96* or 97*. Just a thought...

TurboSDL · #60 05-06-2009, 09:06 PM

my car has been doing the same thing, on the hwy... 100-105c and when i hit it with the infra red thermo- 220f..