Hey all, this is just getting worse and worse in my 1980 300TD. I am really at my wit's end as it just gets louder and louder. It sounds like it's coming from the front right wheel well or at least on the right side, underhood area. I will hear it when going over choppy roads at speed or pretty much any time I am driving faster than 70mph.

I've been under the car a few times for inspection, looked under the hood for anything loose, wiggled the wheel and caliper but haven't found anything obvious...it sounds a little like a ball joint but not quite like that. It's a real hollow clunky sound. I even suspected the hood might be a bit loose and shaking but that's not it.

Fishing for ideas...

Thanks,
Ken

Try bouncing the fender? Sometimes helps locate a front end noise. Check your upper control arm to swaybar area as well for intact bushings etc. The bounce test will even help locate things like shot shock bushings on occasion.

I'll check the links and the anti-roll bar bushes.

__________________
E300TD year 2000. RUSTY SOLD
cost a fortune to maintain on the road
but run well on WVO
Second Merc died due to corrosion ( NOT rust) How can mercedes get away with that for so long?
Third lasted a month then went away...
Fourth now... Corroded too...

Try jacking the car up & lowering it onto a block just under the LCA where the spring is. That takes the load of the ball joints and allows you to properly see if you have any movement especially in the ball joints

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

it could be the wheel bearing

__________________

Upper strut mount is what I would check, but then again, I'm pretty drunk ATM.

__________________
Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles

Johnathan,
If you can come up with a suggestion as good as that when your drunk, imagine how smart you must be when your sober!!
Definitely worth checking.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Most likely culprit is a guide rod mount. If you brake while it is clunking does it go away?
Best way to check as mentioned previous is to jack the tire up(be sure to properly supprt the vehicle) and check for play. Grab the tire at 12 & 6 oclock and try to rock it. Play/noise would indicate ball joints are bad. You should be able to tell if the top or bottom is the problem.
Next grab the tire @ 3 & 9 oclock. Check for play again. This would indicate steering components worn- ie tie rods, idler arm bushing steering shock etc.
To check the guide rod mount I use a pry bar. At its base there is a clamp on the rod. Try to pry it forward. Movement should be minimal. If you get a lot of play(> 1/4") that is the issue.

Good Luck

__________________
81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up

No struts, so no upper strut mount. Bushing at the rear of the radius arm, swaybar bushing in upper control arm, wheel bearings are the big three clunkers, but wheel bearings tend to cause other issues before they start clunking. Ball joints maybe, but usually they squeak quite a bit before they clunk as well.

Worn out UCA bushings cause that as well.

__________________
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

Ken,
Could the noise be described as a POP?
I had my car up on jacks, engine off, and had a friend turn the steering wheel back and forth. I was getting a pop noise that I thought was a sticking tie rod end. I could clearly hear it from inside the car.

It turned out to be the idler arm bushing. When that bushing starts to wear, it no longer rotates properly in relation to the axis of the idler arm housing and starts to stick. That is the noise I was hearing.

I replaced this part with a Lemforder brand (factory OEM) kit and had my front end mechanic replace it today. The idler arm bushing can sometimes be a bear to remove. He had to use his pneumatic hammer and some heat to force the upper one out. The lower one required heat, Vise Grips and a large screw driver. I suspect one could make a puller out of a auto body hammer. Based on what I observed today, the removal of the idler arm bushing could have taken me several hours on my back in the garage.

__________________
84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

Ken,

One more thought. On my previous 300D, the support frame for the rear guide rod mount developed a crack. This would cause an unusual sound, a low level chirp maybe. Make sure you look behind the rear guide rods in and around the welds and support area.

This area can be welded, I think this well equipped front end shop fabricated an additional piece of metal to act as a support for the weld. It wasn't terribly expensive as I recall.

__________________
84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

Wow, thanks for all the speculation, folks! I have been reading and considering all of it. Actually, the idea that seems the most likely to me (based on location of the sound and sound quality) is that the right sway bar bushing is shot.

So, how can I know if I'm right and where can I get new sway bar bushings? Are they really a pain to replace? I can see the little plastic covering that seems to allow access to it when I remove my battery and tray. I don't consider that a big fuss as long as I don't have to remove the whole bar to change the bushings. The drivers side might be a little harder with the booster possibly in the way(?)

Thanks,
Ken

Given the situation and the work required for either, you should go ahead and replace the upper control arms at the same time. New ball joints, new bushings, new swaybar bushings- Nothing wrong with replacing all that stuff in one shot.