1999 E300 Turbo Diesel running Temp 65C-70C. Too cold to pass emissions? - PeachParts Mercedes-Benz Forum

777funk · #1 12-15-2020, 09:07 PM

Would this hurt anything? Ideally I'd like 80C but the old worn out thermostat seems to run at 65C most of the time.

I have to have this pass for the EGR system check soon and wanted to find out if this will hurt anything.

Question now answered by experience... it will pass.

Side note on testers:
O-Reilly's (their tester reads and clears emissions info on this car). Harbor Freight Zurich ZR4 tester ($39.99 and surprisingly it also works!)

barry12345 · #2 12-15-2020, 11:04 PM

Certainly might reduce heater output. Also not considered good to run engines cooler than in there designed range.

Some work required to see if the temperature displayed is accurate. In todays world always check a new thermostst out in hot water. Plus checking out your old one is also a good ideal at the same time.

777funk · #3 12-16-2020, 07:15 AM

We pulled the thermostat (bought a new one first) and it is indeed accurate that it's running cool. It seemed to open at around 160F.

We ran into a problem. Mercedes unfortunately built the thermostat into the thermostat housing on this car meaning that the thermostat we bought cannot be used. It will cost my 16 year old son $55 approx to buy a new thermostat housing and thermostat. Bummer that Mercedes did this on the later OM606 engines.

Diseasel300 · #4 12-16-2020, 09:17 AM

Quote:

Originally Posted by 777funk

It will cost my 16 year old son $55 approx to buy a new thermostat housing and thermostat. Bummer that Mercedes did this on the later OM606 engines.

If a $55 part is creating hardship, sell the car QUICK and get him something Japanese. An old car (especially European cars that live on cash infusions) isn't a great choice for a first-timer learning to drive. They should be learning to drive safely, not worrying about running idiosyncrasies or freaking out about going broke on the next part/service they need to pay for.

More importantly, the thermostat being built into the housing is typical on a large number of 90s and later vehicles from nearly all manufacturers. This isn't just a Mercedes thing.

777funk · #5 12-16-2020, 09:52 AM

Quote:

Originally Posted by Diseasel300

If a $55 part is creating hardship, sell the car QUICK and get him something Japanese. An old car (especially European cars that live on cash infusions) isn't a great choice for a first-timer learning to drive. They should be learning to drive safely, not worrying about running idiosyncrasies or freaking out about going broke on the next part/service they need to pay for.

More importantly, the thermostat being built into the housing is typical on a large number of 90s and later vehicles from nearly all manufacturers. This isn't just a Mercedes thing.

Not really a financial hardship, but he's 16 and it's his money and he doesn't have enough to buy a new car. And at the end of the day the necessities we've already spent a few hundred bucks and there's still more of what I'd consider necessity to come. So we're picking or chosing. We all know it's not 1x$55. It's unlimited amounts of parts we 'could' throw at the car.

And with that said (from experience) MB diesels are cheap to drive... IF... you don't change every last minor piece that's broken, squeaks a little, leaks a few drops a week, or is 'not quite in spec'. I learned this the hard way on my first MB diesel daily driver (87 300D). I spent about $1500 getting it up to snuff changing every last piece that squeaked/rattled plus preventative maintenance (i.e. the OM603 vacuum pump that 'could' shed its bearings) and minor mechanical annoyances (like this temp difference). I probably had a hundred or two work hours into it said and done. I sold the car a few years later in great condition for $1500. Nobody in the buying market cared that I spent what I was selling it for plus my own hours restoring the car to excellent mechanical condition.

So... that said, I won't do that again, especially with my sons money.

But at the same time, I won't discourage him in having a good car and learning to be a diesel fan. I know these engines much better than I would know... say a Honda. We will change things that must be changed (oil, filters, transmission filter, etc). But if you add up all the minor things that 'could' be changed... we're not going there.

Thus the original question... is it a necessity (per the computer to go through it's EGR self test) for the engine to run at 80C to pass emissions or will the current 65C do the job?

Usaguy · #6 12-16-2020, 03:14 PM

Quote:

Originally Posted by Diseasel300

If a $55 part is creating hardship, sell the car QUICK and get him something Japanese...

The japanese don't always get it right. You have to go by specific model/year/tranny

Oil burning toyota 2.4, tacoma frame problems, honda v6 automatics... just to name a few.

777funk · #7 12-16-2020, 05:43 PM

Quote:

Originally Posted by christuna

The japanese don't always get it right. You have to go by specific model/year/tranny

Oil burning toyota 2.4, tacoma frame problems, honda v6 automatics... just to name a few.

Yep and ive had many beater MB diesels that I didn't treat to every last part it asked for (only necessities) and they served me well.

I think an MB diesel is a fine first car even for a 16 year old with a tight budget.

engatwork · #8 12-16-2020, 06:27 PM

Be glad it is not an S class.

argon3030 · #9 12-17-2020, 11:43 AM

A 20+ year old car typically has in excess of 150k miles on it, and every service item imaginable is due or overdue for replacement. Water pump, belt tensioner and rollers, control arm bushings, ball joints, tie rod ends, sway bar links, shocks and struts, strut mounts, engine mounts, transmission mounts, linkage bushings, subframe bushings, brake pads and rotors, brake hoses, change every filter, flush every fluid (brake, diff, tranny, steering, coolant). That's the bare minimum. Not to mention repairing all the features and functions that have broken over the years and were never fixed.

Upon acquisition of any 20+ year old car, my expectation is that I'll drop at least $2k in parts on day one, to refresh all the worn out parts and perform all the deferred maintenance items. I've owned many, and it always is about $2k in parts and 40 hours of experienced DIY. Do it all up front, and then enjoy many years of trouble-free motoring, at a fraction of the cost of buying new.

Take no offense, but I always recommend leasing a car to those unwilling or unable to do this kind of comprehensive servicing on a tired 20+ y/o car. In the end, it will cost less, be more reliable, and be less of a hassle. Plenty of new entry level cars can be leased for $149/mo which is affordable even on a Fast Food paycheck.

speednjay · #10 12-17-2020, 12:02 PM

Not sure where what state your getting smogged. I’m in ca and on my 99 turbo diesel all they did was check for codes and aftermarket stuff. Smog check wasn’t as involved as a gas engine

t walgamuth · #11 12-17-2020, 01:36 PM

Quote:

Originally Posted by 777funk

Not really a financial hardship, but he's 16 and it's his money and he doesn't have enough to buy a new car. And at the end of the day the necessities we've already spent a few hundred bucks and there's still more of what I'd consider necessity to come. So we're picking or chosing. We all know it's not 1x$55. It's unlimited amounts of parts we 'could' throw at the car.

And with that said (from experience) MB diesels are cheap to drive... IF... you don't change every last minor piece that's broken, squeaks a little, leaks a few drops a week, or is 'not quite in spec'. I learned this the hard way on my first MB diesel daily driver (87 300D). I spent about $1500 getting it up to snuff changing every last piece that squeaked/rattled plus preventative maintenance (i.e. the OM603 vacuum pump that 'could' shed its bearings) and minor mechanical annoyances (like this temp difference). I probably had a hundred or two work hours into it said and done. I sold the car a few years later in great condition for $1500. Nobody in the buying market cared that I spent what I was selling it for plus my own hours restoring the car to excellent mechanical condition.

So... that said, I won't do that again, especially with my sons money.

But at the same time, I won't discourage him in having a good car and learning to be a diesel fan. I know these engines much better than I would know... say a Honda. We will change things that must be changed (oil, filters, transmission filter, etc). But if you add up all the minor things that 'could' be changed... we're not going there.

Thus the original question... is it a necessity (per the computer to go through it's EGR self test) for the engine to run at 80C to pass emissions or will the current 65C do the job?

I don't know about the emission question but would recommend putting in the right stat that the engine is designed for. Specifically it is bad for your bearings to run them cold.

777funk · #12 12-17-2020, 02:21 PM

Sounds like it's an unknown on the onboard readiness monitor check being based on run temp.

In an ideal world, every loose or worn part would be changed. We've changed what was needed (one bad tie rod end, motor mounts, filters, center driveshaft bearing, fuel system o-rings) and will stop there. It'll most likely be ok without babying further. Been there done that and daily driven many of my vehicles this way. All of my vehicles are 2003 or older and though shocks squeak some, clunk at times, they work just fine, start any time needed, get from point A to point B. Brakes and safety items are good, engine and trans work as intended. I stop there. I don't care about heated seats, or in my own personal car even heat for that matter. I can wear a coat in the winter. I do like A/C to work in the summer.

This one is a temporary first car that my son can learn to drive in and put a few dents in (hopefully not!!) without feeling too bad about it. It'll work just fine for that: ) It's actually a pretty nice car for what he has in it.

MY_DADS_RIDE · #13 12-19-2020, 01:52 PM

Normally I just garner information threads to do my own dirty work repairs. Upon seeing this issue, it relates to similar symptom I'm having on my newly acquired 99 E300d.
I have replaced the housing(85degree stat included)with same results. I'm not comfortable with it running around 70 still. I'm moving on to the coolant sensor.

As a sidebar, the previous posts hold merit in the truth of owning one of these. I've been down this road many times with 20-30 yr old specimens that need a variety of repairs that are age - not necessarily mileage related. I knew my 126's intimately out of need due to the lack of mechanics named Fritz or Hans who knew how to work on these diesels.
After acquiring my current W210, I'm realizing how much I miss the straightforward simplicity in the 123,124,126.
The early electronics incorporated into the W210s are frustrating at best, along with the build materials, particularly plastics.
I'm currently in a conundrum after messing something up after installing new seals on the injection pump...probably moved the delivery valve pistons and the thought of opening it to re-seat the guide pins has created major anxiety.
With that said, it would seem a decision should be made as to the reality of what your son is willing to spend in time and money on his car to keep it running and its difficult to forecast repairs to avoid potential disaster...like you said about your vacuum pump possibly barfing out the bearings. Been there and replaced it out of fear, not need.

I'll suggest a couple things to get his car smoged.
- Replace coolant sensor ($15-20) or if you can check its accuracy.
-Remove thermostat temporarily . Unfortunately, because they incorporate the stat into the housing, you may have to get a new one anyway unless you can find an older style housing at a parts yard.
Good luck and kudos for your 16yr old getting in to older Benz diesels.