Hello TD bros. I have some questions about our engine, being new to it and all.
1. My car starts great, but I have noticed after the glow plug light goes out, the green light never comes on. Does this mean the glow plugs arent working? SOLVED: bad glow plugs.
2. Under hard acceleration I can hear a whine from either the dash or under the hood. Could this be tach noise or a possible leak? SOLVED: Intake leak.
3. My car idles a little high, where do I adjust the idle speed and what is the OEM RPM? It's currently at about 1k and make the rear drop when put in gear etc. FIXED
4. When accelerating hard, it doesn't feel like it will go WOT. I am honestly afraid to punch the gas to WOT out of fear it will blow up or something. I am new to diesels, so am I just expecting an easier power band? I have a solid turbo and getting boost (although the whine mentioned above could be a boost leak in theory). I'm not trying to drag race the car or anything, I occasionally like to let my vehicles rip to get the juices flowing and crap blown out. SOLVED: Car is old. Needed some cleaning and tuning.
5. Is it normal to have a bit of marbles in a can from the motor on start up? It smooths out after a couple of minutes. Its not super loud either, but noticeable. Its not a knock, ping, or tick. Again, new to diesel so don't know if this is fine. SOLVED: This ended up having something to do with my accessory belts. Went away with new properly tightened belts.
6. The P/O deleted the EGR via pulling the hoses and I am hoping a block off plate. I put metal in the EGR to intake tube to block it off just in case he didn't. Is that an effective location to block it off? Or does it have to be on the manifold?
7. Does anyone have a part number/link to timing belts? I inspected mine, its not in the "Oh shit" territory yet, but I'd like to just change it anyway. Having trouble finding a definitive one.
I will say that this car (1986 524TD 127k mi) runs super well, starts great, shifts great, and sounds good most of the time. Really excited to give it some more TLC and hopefully a gradual restore. Not looking to build the motor up at all. Keeping it stock and rehabbing it is my goal. I intend to rebuild it if it ever gives me trouble. I am guessing the transmission will give me a fight before the motor does, judging by the feeling of the two.
Thanks! Sorry for the huge list, I am having trouble finding active sites for this car!
M21 Questions
M21 Questions
Last edited by joemangx on Sep 21, 2017 4:28 PM, edited 1 time in total.
Re: M21 Questions
All of those are googleable.
1 glow plugs are on only for starting
2 the whine is the turbo
3 idle is high at start but once warm lowers
4 its an 80's oil crisis diesel not a performance machine
5
6
7 bavauto.com
1 glow plugs are on only for starting
2 the whine is the turbo
3 idle is high at start but once warm lowers
4 its an 80's oil crisis diesel not a performance machine
5
6
7 bavauto.com
Re: M21 Questions
Thanks for the reply but I don't think you read my questions thoroughly.Kopek130 wrote:All of those are googleable.
1 glow plugs are on only for starting
2 the whine is the turbo
3 idle is high at start but once warm lowers
4 its an 80's oil crisis diesel not a performance machine
5
6
7 bavauto.com
1. I am aware of what glow plugs are and their purpose. My question is regarding the lack of a green start light once the glow plug light turns off on the dash. I've read that this indicates a fault with one or more of the plugs.
2. That's kind of vague. I'm hoping you're not implying that I'm mistaking the turbo spooling for the whine lol. This sounds like a tach whine, potentially from under the hood.
3. I have the opposite actually, but I figured this one out. My throttle isn't returning fully and is raising my idk by about 500-700 RPM. Pretty sure the springs are gunked up on the IP.
4. This is not useful whatsoever. And an update to my original question regarding this: I put the pedal to the floor and it wouldn't go near redline. Came up short about 1k RPM. Normal?
7. Thank you for the link, I'll check it out.
Re: M21 Questions
1 yup that's correct,download the electronic manual (in this website) it's extremely valuable. Do what you can before you start turning wrenches. If you have cruise control your cable loom to that computer goes through the intake manifold and into passenger glove box (hilarious right). Get a test light to ensure continuity. I got the "gasket minus head-gasket set" from pelican parts that has a lot of other gaskets (valve cover, exhaust, intake, etc) for $90.
2 other whine could be the ambient air temperature sensor in driver's side panel, it's a air suction sound
4 I would not worry about it, as long as you have some sort of power and you feel that turbo kick in at 2500+ then leave it. Sorry I know it is not helpful.
7 bavauto is where I got timing belt, water pump, and a lot of stuff
What is your final goal for the restoration?
2 other whine could be the ambient air temperature sensor in driver's side panel, it's a air suction sound
4 I would not worry about it, as long as you have some sort of power and you feel that turbo kick in at 2500+ then leave it. Sorry I know it is not helpful.
7 bavauto is where I got timing belt, water pump, and a lot of stuff
What is your final goal for the restoration?
Re: M21 Questions
I ended up having a leak in my intake tubing. Sorted out the whine. That restored some power as well once fixed. Feels great now. I'm trying to determine what the noise coming from the engine is. It sounds like a rubber ball in a can and is most noticeable at idle. It's coming from the center, top area of the engine. Maybe an injector or something. It's not a knock or tick.Kopek130 wrote:1 yup that's correct,download the electronic manual (in this website) it's extremely valuable. Do what you can before you start turning wrenches. If you have cruise control your cable loom to that computer goes through the intake manifold and into passenger glove box (hilarious right). Get a test light to ensure continuity. I got the "gasket minus head-gasket set" from pelican parts that has a lot of other gaskets (valve cover, exhaust, intake, etc) for $90.
2 other whine could be the ambient air temperature sensor in driver's side panel, it's a air suction sound
4 I would not worry about it, as long as you have some sort of power and you feel that turbo kick in at 2500+ then leave it. Sorry I know it is not helpful.
7 bavauto is where I got timing belt, water pump, and a lot of stuff
What is your final goal for the restoration?
Also, is it safe to dump the CCV line to atmosphere? I don't want to keep getting oil in my airbox etc. The oil separator seems to be leaking some blow by as well. Are those regular service interval items?
My restoration goal is to get the car running proper, eliminate any noises associated with worn/loose parts, clean up the interior, and just get it to a clean factory state. I'm not planning to make it a show car or get any more power out of it.
Re: M21 Questions
The "marble bouncing around sound" definitely does not sound OK.
One thing that can be verified from talking to you is you don't have hesitation or rough idle, and even a gain in power means the intake side is sealed.
Go to Mercedes Source on YouTube regarding turbo inspection and diagnostic. Make sure that the turbo is not bouncing around.
I doubt it's anything in the intake as its completely absolutely coated with sludge eliminating marble bouncing around sound.
What about exhaust color? Black or blue? Blue at idle and acceleration? Take notes on when specific things happen.
One thing that can be verified from talking to you is you don't have hesitation or rough idle, and even a gain in power means the intake side is sealed.
Go to Mercedes Source on YouTube regarding turbo inspection and diagnostic. Make sure that the turbo is not bouncing around.
I doubt it's anything in the intake as its completely absolutely coated with sludge eliminating marble bouncing around sound.
What about exhaust color? Black or blue? Blue at idle and acceleration? Take notes on when specific things happen.
Re: M21 Questions
I wouldn't say it's a marble sound, it sounds non metallic. It could potentially be something loose externally on the engine. The noise is not coming from the turbo, I checked that for shaft play and it was minimal, but not perfect.
Is there a trick to getting the throttle springs working like new? I'm having a high idle situation because the throttle doesn't fully snap back. And today actually, I parked it and it starting surging until I hit the gas pedal. There's sludge in the springs and I tried to get as much off as possible but clearly that didn't help.
Is there a trick to getting the throttle springs working like new? I'm having a high idle situation because the throttle doesn't fully snap back. And today actually, I parked it and it starting surging until I hit the gas pedal. There's sludge in the springs and I tried to get as much off as possible but clearly that didn't help.
Re: M21 Questions
While the car is running spray (lightly) water on the belts. Spin the fan. Feel for play. Check the engine mounts.
If the sound is not metallic, then the noise being made is not metal on metal.
My next project for mine is a 5 speed swap. Same scenario as you but would love to do this 5speed swap.
If the sound is not metallic, then the noise being made is not metal on metal.
My next project for mine is a 5 speed swap. Same scenario as you but would love to do this 5speed swap.
Re: M21 Questions
I would love to have a manual in this car. The automatic really hinders the cool factor of the diesel.
I fixed my throttle issue, the return cable wasn't connected for whatever reason. My idle is now at around 800RPM. My heat shield vibration is mostly gone with the adjusted idle as well so that's nice.
https://youtu.be/uShscXf8PNQ
I shot some video on my phone trying to capture the engine noise. You can hear it best in the first clip in the video thanks to the drive thru amplifying the noise. It's not actually that loud. Normally, you can only hear it within the car or by putting your ear to the engine. It's hard to tell but it seems to be only while idling. Certainly possible that the loud diesel engine just drowns the sound out at higher engine speed.
I fixed my throttle issue, the return cable wasn't connected for whatever reason. My idle is now at around 800RPM. My heat shield vibration is mostly gone with the adjusted idle as well so that's nice.
https://youtu.be/uShscXf8PNQ
I shot some video on my phone trying to capture the engine noise. You can hear it best in the first clip in the video thanks to the drive thru amplifying the noise. It's not actually that loud. Normally, you can only hear it within the car or by putting your ear to the engine. It's hard to tell but it seems to be only while idling. Certainly possible that the loud diesel engine just drowns the sound out at higher engine speed.
Re: M21 Questions
So the thumping sound is definitely not the fan flapping around I guess.
The last time I had a thumping sound sorta siiimilar to that, was when early on (remember, it was my parents bmw, it was always taken to the dealer) and the first thing I did was change the oil to a synthetic blend liquid moly 15w40, choosing that from researching in lots of forums. But it just didn't sound like it used to when it got to operating temp, and some blue smoke in the exhaust.
When I went on a 6 hour scavenger hunt talking to shops in person, it turns out that the Bavarian expert here in Virginia uses Shell Rotella T (Shell is now rebadging Rotella "T" as T4). It turns out that this was what the bmw dealer was using in my parents car, per recommendation they got from the private Bavarian shop owner, and not the synthetic blend. It really was hilarious because I had to push (kindly) through the parts guys in order to get a mechanic's recommendation. Our original mechanic retired (we never did meet the guy)
I've also noted that the Mercedes private shops were using the Liqui Moly synthetics, but not BMWs (hence why I tried Liqui Moly synthetic in the first place). Remember we are talking specifically 80's diesels.
I was also able to verify this by using an oil gauge. The findings were:
idle Rotella- Cold: 50psi, 80C warm- 20psi, 90C+ hot- 18psi, 100C real hot- 16psi
idle Synthetic- Cold: 30psi, 80C warm - 17psi, 90C hot - 12psi
When at 2500+ RPM, the Rotella had consistently higher PSI readings. The Synthetic was just way too low compared to the specs. The specs manual specifies oil pressure at idle between 7-28psi, at max speed 57-85psi.
https://www.bmwtechinfo.com/repair/main/247en/index.htm
The last time I had a thumping sound sorta siiimilar to that, was when early on (remember, it was my parents bmw, it was always taken to the dealer) and the first thing I did was change the oil to a synthetic blend liquid moly 15w40, choosing that from researching in lots of forums. But it just didn't sound like it used to when it got to operating temp, and some blue smoke in the exhaust.
When I went on a 6 hour scavenger hunt talking to shops in person, it turns out that the Bavarian expert here in Virginia uses Shell Rotella T (Shell is now rebadging Rotella "T" as T4). It turns out that this was what the bmw dealer was using in my parents car, per recommendation they got from the private Bavarian shop owner, and not the synthetic blend. It really was hilarious because I had to push (kindly) through the parts guys in order to get a mechanic's recommendation. Our original mechanic retired (we never did meet the guy)
I've also noted that the Mercedes private shops were using the Liqui Moly synthetics, but not BMWs (hence why I tried Liqui Moly synthetic in the first place). Remember we are talking specifically 80's diesels.
I was also able to verify this by using an oil gauge. The findings were:
idle Rotella- Cold: 50psi, 80C warm- 20psi, 90C+ hot- 18psi, 100C real hot- 16psi
idle Synthetic- Cold: 30psi, 80C warm - 17psi, 90C hot - 12psi
When at 2500+ RPM, the Rotella had consistently higher PSI readings. The Synthetic was just way too low compared to the specs. The specs manual specifies oil pressure at idle between 7-28psi, at max speed 57-85psi.
https://www.bmwtechinfo.com/repair/main/247en/index.htm
Re: M21 Questions
It's not really a thump. Its so hard to explain or record the noise. It did it when I got the car and after I changed the oil to Rotella T4. I run that oil in EVERYTHING.
I figured out this morning that the noise does go away with RPM. It is only truly present at idle. I'm really thinking it's in the timing belt area. Maybe a bad tensioner pulley or a water pump beginning to go. I'm at a loss. Someone on Reddit in the diesel page said to check for intake and boost leaks, but I can't fathom how that would make this noise and cause no power loss.
I figured out this morning that the noise does go away with RPM. It is only truly present at idle. I'm really thinking it's in the timing belt area. Maybe a bad tensioner pulley or a water pump beginning to go. I'm at a loss. Someone on Reddit in the diesel page said to check for intake and boost leaks, but I can't fathom how that would make this noise and cause no power loss.
Re: M21 Questions
Engine does not shake either? (lol a diesel not shaking)
Can you link that reddit thread? I don't know how to use reddit. I've tried searching using that site but I cannot figure it out.
Now that I listen to it again the sound definitely is not in time with any ignition timing, as in, it's completely random.
Can you link that reddit thread? I don't know how to use reddit. I've tried searching using that site but I cannot figure it out.
Now that I listen to it again the sound definitely is not in time with any ignition timing, as in, it's completely random.
Re: M21 Questions
It shakes a little bit at idle, but nothing I wouldn't expect from an old diesel.
https://www.reddit.com/r/Diesel/comment ... 4td_noise/
EDIT: I am 95% sure it's the water pump. It's getting louder every day, and now that it's louder I can actually put my ear in front of the radiator and hear the noise coming from behind the radiator. It is at it's worst when it's cooled off and mellows out when hot but it's getting more and more consistent. The car is parked until parts come in this week. Changing the water pump, belt tensioner, and the timing belt while I'm in the area. The sound now matches most YouTube videos of bad water pumps. If that ends up being the fix, I'll be glad it was that and not anything worse.
https://www.reddit.com/r/Diesel/comment ... 4td_noise/
EDIT: I am 95% sure it's the water pump. It's getting louder every day, and now that it's louder I can actually put my ear in front of the radiator and hear the noise coming from behind the radiator. It is at it's worst when it's cooled off and mellows out when hot but it's getting more and more consistent. The car is parked until parts come in this week. Changing the water pump, belt tensioner, and the timing belt while I'm in the area. The sound now matches most YouTube videos of bad water pumps. If that ends up being the fix, I'll be glad it was that and not anything worse.
Re: M21 Questions
This weekend I replaced the timing belt, water pump, timing belt tensioner, adjusted the valves, and replaced the accessory belts.
What I learned: the fan can be a nightmare with the wrong tools. Bought a 32mm wrench from HF and a narrow ratchet strap for a pulley holder and it came off with minimal effort in less than a minute.
Pinning the crank and IP is a breeze with the specialty tools. A camshaft holder is a nice tool to have as well.
The water pump was indeed worn out, but not bad enough to cause noise or overheating. Replaced Anyway. Same story with the tensioner.
The valves were out of spec but not by a whole lot. Adjusted them to .30mm/.12in Anyway. Most of the eccentric lock nuts were super tight making it kind of stressful, especially on #5/#6.
All 3 of my accessory drive belts were poorly tensioned and cracking. Kept the A/C belt off since I can't seem to find the right size. The belt I received is just too short.
The effects of these repairs:
After getting everything reassembled and double checking everything was aligned I fired the car up. I proceeded to hear awful belt screeching and the NOISE in question in the posts above was actually LOUDER. Shut the car off, decided my idea of belt tension is clearly way off and tightened them. Belt screeching is gone, and the noise is gone too. So I'm thinking all along it was related to the power steering belt/pump. All of the bolts were loose. I'm going to drive it for a while and see if it comes back. So all in all, I have peace of mind knowing the whole front end of the motor is fresh and the car runs smooooooth after the valve tweaks. I may have lost a little bit of "balls" under hard throttle but nothing significant. Only getting smoke at full throttle. Pretty pleased. Couldn't have done it without the resources on this site.
Next projects: disable ABS (kicking in at random times), install new condenser and dryer, change fuel filter, and go through the suspension and see what it needs. Then on to the interior and maybe the paint.
What I learned: the fan can be a nightmare with the wrong tools. Bought a 32mm wrench from HF and a narrow ratchet strap for a pulley holder and it came off with minimal effort in less than a minute.
Pinning the crank and IP is a breeze with the specialty tools. A camshaft holder is a nice tool to have as well.
The water pump was indeed worn out, but not bad enough to cause noise or overheating. Replaced Anyway. Same story with the tensioner.
The valves were out of spec but not by a whole lot. Adjusted them to .30mm/.12in Anyway. Most of the eccentric lock nuts were super tight making it kind of stressful, especially on #5/#6.
All 3 of my accessory drive belts were poorly tensioned and cracking. Kept the A/C belt off since I can't seem to find the right size. The belt I received is just too short.
The effects of these repairs:
After getting everything reassembled and double checking everything was aligned I fired the car up. I proceeded to hear awful belt screeching and the NOISE in question in the posts above was actually LOUDER. Shut the car off, decided my idea of belt tension is clearly way off and tightened them. Belt screeching is gone, and the noise is gone too. So I'm thinking all along it was related to the power steering belt/pump. All of the bolts were loose. I'm going to drive it for a while and see if it comes back. So all in all, I have peace of mind knowing the whole front end of the motor is fresh and the car runs smooooooth after the valve tweaks. I may have lost a little bit of "balls" under hard throttle but nothing significant. Only getting smoke at full throttle. Pretty pleased. Couldn't have done it without the resources on this site.
Next projects: disable ABS (kicking in at random times), install new condenser and dryer, change fuel filter, and go through the suspension and see what it needs. Then on to the interior and maybe the paint.