ticking noise at start up 85 190e - PeachParts Mercedes-Benz Forum

tunk · #1 08-21-2003, 05:31 PM

Hey folks,

Again, I don't drive the car too often now that the weather is nice for biking, which allows me serious time to do work.

Here's the question, car runs fine, but when I start it up the oil pressure doesn't come up to 3 bars for maybe four seconds not a long pause and it always comes up but a little pause. during that time and for a couple of seconds afterwards there is a distinct ticking noise coming from the engine. The oil pressure can be bumped up quicker if I give it a little gas. If I give it some gas the ticking sound goes away as well instantly. The car never, ever, makes any noise once it has warmed up for a minute or two, not at lights idling, not on the highway. nothing. only at start up, when it is cold. doesn't do it, now that I am thinking about it, if I drive somewhere and restart the car when its warm. car has 189,000 miles and I picked it up from PO with 184,000 and have no idea what if anything in the way of service has been done by PO, but I have swapped all fluids filters and cap wires etc.. little stuff...

Main question is what might be causing the ticking noise at start up. And can someone who changes fluids and tinkers with sunroofs and has an interest and time reasonably fix as DIY project. Any/all thoughts welcome...

Thanks,
CDT

earossi · #2 08-21-2003, 11:08 PM

More than likely, you have a hydraulic lifter that has leaked down and may be fouled with dirt or other material that has built up over the years. When you first start up cold, there is a very short period (3 to 5 seconds) needed for the oil pump to repressure the system and pump up the lifter. Though you may find the tapping noise objectionable, you are not doing any measureable damage to the engine to leave it "as is". You can add some solvent (many commercially available solvents out there that profess to clean up "dirty" engines), or replace the the lifter (a nice project for a DIY person).

xp190 · #3 08-21-2003, 11:34 PM

I would say that this is the timing chain hitting the timing cover. It is a well know fact that the tensioner for the chain has been updated to eliminate this problem.

What happens is the tensioner depends on oil pressure, and when there is no oil pressure, there is a lot of slack on the chain and on startup it will hit the timing cover. The updated tensioner works like a ratchet, so once it is tightened, it will stay in the same position and eliminate this.

If it is not the chain, it could be valve noise. I had this happen when my car was running on cheap gas. Switching to a higher brand fixed it right away.

xp

earossi · #4 08-22-2003, 09:07 AM

I agree that the noise could be a slack chain, but the type of noise a lose chain produces is more of a clatter, not a ticking sound. At least that has been my experience. If it is a chain tensioner, then it should be fixed and not tolerated.

tunk · #5 08-22-2003, 10:14 AM

there's no question it is a tick. It is also a regular non chaotic sort of noise, by that I mean that you hear the tick every say half second not all at once clattering and random but a steady tick tick tick tick, as if one cylinder (or lifter) is doing something weird. But... If I take off the valve cover will I be able to determine whether it is a chain or a lifter? I'll do a search but what do people look at when they look at the chain for signs of age and stretching? and the same for the lifters.

Thanks for the help,
CDT

sbourg · #6 08-22-2003, 10:46 AM

If it counts, I vote lifter. I have never had either tensioner or hydraulic lifter problems, but the latter jibes better with low initial oil pressure, and 'ticking' is a typical lifter sound.

Steve

johnathan1 · #7 04-04-2008, 03:48 PM

I know this thread is absolutely ancient...but my 89' 300SEL just started doing this weird cold startup tapping sound... And I was wondering how would one determine which lifter is making the tapping sound?

earossi · #8 04-04-2008, 05:48 PM

You're right that it has been a long time since this string ran!

But, let's see if I can give some guidance.

First off, if it is just a "tick....tick....tick" sound ONLY on startup of a cold engine and IF the noise quickly quiets down (in less than 20 seconds), my guess is that you have a sticking lifter. What happens to the lifters is that oil pressure pumps them up and as soon as you shut down the engine, the lifters will leak out some of the oil that had been pressurized (normal). There is a single very small hole in the side of each lifter that allows the pressured oil into the lifter. If any varnish has built up in that hole that would restrict the flow of oil to the lifter; or if there is any varnish buildup in the bore of the lifter, then the portion of the lifter that "lifts" will move more slowly then normally. Either of these scenarios will produce the "noisy lifter".

You can isolate it using a stethoscope (inexpensive) that will allow you to put the probe on different components of the engine, and will provide an amplified sound of what is noisey in the immediate area.

So, what is the fix. Well, you could remove the cams and pull all the lifters and have them chemically cleaned. Or, if they have a huge number of miles on them, you may want to choose to buy new ones. Given the age of your car, I assume that it has a great deal of miles on it and does not have enough value left in it to justify a cost of a couple thousand dollars. So, replacing the lifters is a problem. However, if you every have a head job done on the car, the lifters will be accessible and should at least be cleaned.

What I would suggest is trying some super solvents that will attack sludge and varnish.

Kroil Company (mailorder) has a wonderful line of products. You will find them on the internet. At any rate, they make a product called (I believe) Motor Medic.....or Motor Prep....something like that. You'll have to go through their website to find the right chemical. However, it will be advertised as a motor clean up that dissolves sludge.

The good news is if the condition stays the same as you now describe it.....then there is no damage to your engine.....just some annoyance on your part.

johnathan1 · #9 04-04-2008, 08:01 PM

Well, my engine only has 140k miles on it...and it doesn't do the tapping all the time. I guess I'll try some solvents...would an oil for "high mileage engines" like Valvoline Maxlife be a good idea?

earossi · #10 04-04-2008, 11:10 PM

I honestly don't know anything about the oils you were suggesting as a possible remedy. Other than try one of the solvents I mentioned, I would just learn to live with the tapping as long as it goes away right after the engine starts up. The noise does not indicate any damage being done. At 140K miles, I'm surprised that more of the lifters don't clatter!