Knocking at idle? Sounds Like a Diesel

[YUPOK]

There are at least a dozen of these articles but none specific to my symptoms.

I just put the car together, its a 95 talon TSI AWD with a 6 bolt swap. Everything is stock. The engine sat for a while inside a warm garage so I knew I would have lifter bleed issues. This is more of a knocking like a diesel but only at ide. The car itself is quiet, can't hear the knock from behind the car and it seems more from the intake side. It idles fine and has no backfire or stalling issues. Once I get up over about 1300 rpm it clears out. I am running 87 pump gas and 5-40 oil. 5 degrees advance from the 1G CAS.

Any thoughts?

 

[VtecvrsTurbo]

First off, don't use 87 octane gas ever again. If you can get 93, use it. If not 91 is good enough. 5 weight oil is too thin IMO and would switch to 10-30.
It's hard to say, but it does sound like lifers to me. Every 4g63 should have 3 revised lifters installed to get rid of any confusion about ticking/knocking.
Use the hollow pipe trick to find the knock.

 

[YUPOK]

I'm going to date myself here but what is IMO?

I will add better gas and change the oil and see how that works.

Thanks.

 

[Breezio69]

"In my opinion"

It also seems like it would be lifter tick to me, based on the description and weight of oil. When I replace my valve seals ill be throwing in 3g lifters for this same reason. Every cold start for about 2-3 minutes my car sounds like death.... along with the touch of smoke from some valve seals that are bad.... I get some looks, haha.

 

[DSM1G90]

87 ain't gonna hurt on a 6bolt as long as the turbo doesn't spool up to full peak (like doing casual town driving and freeway driving) due to the low compression a 6 bolt runs on.

Knock sensor tell the ECU to retard timing if it detects knock..and motors don't knock at idle.

But if you have excessive knock, 91 fuels will suffice and cure the issue. 93 is almost an overkill unless your motor is heavily modded, but by your description with being stock, 91 will be fine to use.

If it's heavy knock at idle, motor has oil pump issues with rod knock, or a connecting rod bearing has been spun.

What are the oil pump readings when the motor is at idle-show adequate pressure?

If the pressure is good, then you got tired lifters that bleed out the oil and needs replacing .. and 3G lifters are not really the right answer since with the larger opening, takes more pressure to keep them filled. Stock lifters doe the job nicely.

True though: you need the 10w30 oil as a minimum weight since DSM motors don't have the tight tolerances as some other motors can work with.

 

[YUPOK]

That was very helpful. I only drove the car once, I drove up and down the street 3 times, only got into second and wasn't pounding on it or anything. It does get a little better when warm. I agree the fuel should not matter for a stock setup. Higher octane is needed for an under boost condition to prevent detonation etc. This thing has mostly been at an idle so far.

Oil pressure is my next stop. I know it's getting oil because I ran my oil feed line from the head and it leaked when I first fired it up. Also if I pull the oil fill cap at an idle I can see oil splashing around in there.

Lifters are very possible, the engine has 10K miles on it and was in a 97 GST that was wrecked. The engine was pulled and put on a stand in my buddies garage but still sat for a while. I don't think it's rod knock cause it sounds more like upper engine and only on the intake side but is consistent side to side. If one rod bearing spun it would be very specific and only get worse when driven so I don't think it's that.

Ok, I got some work to do, change oil, check lifters and oil pressure. If that doesn't fix it I'll post again.

Thanks!!

 

[95GSTowner]

That was very helpful. I only drove the car once, I drove up and down the street 3 times, only got into second and wasn't pounding on it or anything. It does get a little better when warm. I agree the fuel should not matter for a stock setup. Higher octane is needed for an under boost condition to prevent detonation etc. This thing has mostly been at an idle so far.

Oil pressure is my next stop. I know it's getting oil because I ran my oil feed line from the head and it leaked when I first fired it up. Also if I pull the oil fill cap at an idle I can see oil splashing around in there.

Lifters are very possible, the engine has 10K miles on it and was in a 97 GST that was wrecked. The engine was pulled and put on a stand in my buddies garage but still sat for a while. I don't think it's rod knock cause it sounds more like upper engine and only on the intake side but is consistent side to side. If one rod bearing spun it would be very specific and only get worse when driven so I don't think it's that.

Ok, I got some work to do, change oil, check lifters and oil pressure. If that doesn't fix it I'll post again.

Thanks!!

Do you still have balance shafts? My 91 GSX was doing the same thing and it was the front balance shaft. The bearing popped out and the hole was egg shaped from all the knocking. I could only hear it at idle

 

[KuckFatrina]

My car had similar issues when I first got it. At idle it sounded like bad lifter tick but once I increased the revs it went away. Turns out the rear balance shaft was destroyed and was sitting in the bottom of my oil pan. Might as well pull the pan to be sure.

 

[DSM1G90]

A lot of users have 15w/40 in the crankcase - a bit more thicker but enough body to fill the tolerances.

I run simple 10w/30 SYN all year around since I do casual town and freeway driving (I do give it a nice blip when passing and such) and don't beat the crap out of my motor..and I'm stock as well.

20w/50 is more like having molasses in the oil pan which is a major overkill for a stock motor that doesn't need that thick oil.

 

[jdezmit]

5w40 is just fine for a stock engine. 5w oil cold is much thicker than a 40w hot, so it has plenty of viscosity for cold starts. I would look for other issues before I blame viscosity.

 

[VtecvrsTurbo]

87 ain't gonna hurt on a 6bolt as long as the turbo doesn't spool up to full peak (like doing casual town driving and freeway driving) due to the low compression a 6 bolt runs on.

Knock sensor tell the ECU to retard timing if it detects knock..and motors don't knock at idle.

But if you have excessive knock, 91 fuels will suffice and cure the issue. 93 is almost an overkill unless your motor is heavily modded, but by your description with being stock, 91 will be fine to use.

If it's heavy knock at idle, motor has oil pump issues with rod knock, or a connecting rod bearing has been spun.

What are the oil pump readings when the motor is at idle-show adequate pressure?

If the pressure is good, then you got tired lifters that bleed out the oil and needs replacing .. and 3G lifters are not really the right answer since with the larger opening, takes more pressure to keep them filled. Stock lifters doe the job nicely.

True though: you need the 10w30 oil as a minimum weight since DSM motors don't have the tight tolerances as some other motors can work with.

I agree with your point on 87 octane being fine under "normal driving" conditions, but why limit yourself to that and not just spend 30c more a gallon and avoid any possible detonation issues. I dont think anyone should run 87 on any turbo DSM enigne (even the lower compression 6bolt) and wouldn't recommend it being "fine".

Who wants to putt around town?

5w40 is just fine for a stock engine. 5w oil cold is much thicker than a 40w hot, so it has plenty of viscosity for cold starts. I would look for other issues before I blame viscosity.

Running a 5w oil isn't fine . That's too thin for the tolerances on this engine.

 

[jdezmit]

[/QUOTE]Running a 5w oil isn't fine . That's too thin for the tolerances on this engine.

Oil--------cSt at 40C----cSt at 100c
5w40-------88-------------14
10w30------70-------------10

The viscosity (ASTM D-445) of a 5w40 is higher at 40c then a 10w30. What is your conclusion of a 5w40 being 'too thin' based on?

For the OP, I am unsure what the issue is, I am just trying to prove that the oil is not the root cause.

 

[YUPOK]

During some tests last night, we discovered several things. The engine has almost new 3G lifters installed, it does have a balance shaft elim kit and my oil pressure up top was low at idle. Found out that the oil filter housing gasket was in really bad shape and pieces were in the ports restricting flow. This explains why it got better with RPM and it got better once warm. So I replaced the gasket and blew through all the ports. Did a leak test and found two small intercooler pipe leaks. Fired it up and realized I forgot to put the oil plug off the head back in where I had an oil pressure gage. Finished up cleaning the Exxon Valdez incident and put fresh 5-40 mobil in.

Started up and she ran really nice, no more knocking. So what it came down to was dry lifters from lack of oil pressure because of a bad gasket.

Now I just got to fix one exhaust leak and figure out what's wrong with the gas gage.

I will probably run a medium grade gas once it's officially on the road.

 

[VtecvrsTurbo]

Oil--------cSt at 40C----cSt at 100c
5w40-------88-------------14
10w30------70-------------10

The viscosity (ASTM D-445) of a 5w40 is higher at 40c then a 10w30. What is your conclusion of a 5w40 being 'too thin' based on?

For the OP, I am unsure what the issue is, I am just trying to prove that the oil is not the root cause.

First you are incorrect. The first number in multi-grade oil is "cold temp" which in our example is 5W and 10W. You telling me that at "cold temp" (40C) that 5-40w oil is thicker than 10-30w?!

And second, I never remember telling him that the "root cause" is from his oil, I said....

Running a 5w oil isn't fine . That's too thin for the tolerances on this engine.

(Service Manual)

So before you attempt to "Flame" my post, please do some research yourself. Thanks.

Here's one of many sources 10-30 Vs. 5-40 Motor Oil | eHow

OP: Im happy you got it figured out!

 

[DSM1G90]

10w min weight oils help from getting lifter tick since it's just thick enough to keep pressure in the lifters..5w gets a little thin and the lifters can't operate fully at the reduced pressure of the thinner oils...and these are stock lifters we're talking about.

One drops in 3G lifters and don't even think in using 5w/x oil since the larger opening can't keep the pressure up for needed operation - why the 15w/x to 20w/x oils.

 

[1G Eclipse94928]

I will probably run a medium grade gas once it's officially on the road.

Please just sell the car instead.
Seriously, run 91+... Its already bad enough.

 

[renovatdkitchen]

Congrats on finding the problem OP. Had the same issue with a rebuild where there was some crap in the Ofh that had to be blown out. Gave me no oil pressure on the first start which was pretty scary.

As for the oil, I ran 5w-30 in mine during the winter and switch over to something heavier (whatever is on sale) for the summer.

The 2G takes 15-50, but is only a summer car.

As for the gas, run a mid grade at the minimum. High grade is recommended for sure though. Don't turn up the boost unless you're running 91+.

 

[NHerron]

Really surprising arguments in here..

The fact is, 5w30 is not too thin. It is in the factory service manual as preferred. And 5 weight being thicker than 40 weight? Hmm. Maybe this thread should be named KISS..

 

[DSM1G90]

It is in the factory service manual as preferred

Maybe for a 420A Dodge, 4G37 (1.8L) or the 4G63 NT motor, but not for a turbo motor since the turbo bearings needs the thicker oil since the oil IS the bearing for the turbo shaft and the shaft "floats" while it spins in a film of oil.

Do something thinner and the shaft suffers from skirting into the metal of the turbo frame.

My Ply manual fully states either a 10w30, or a 20w/20 oil in the warm climates. Maybe a 5w/30 in cold climate condition, but that's pushing it.

It's the lower number that we need to pay attention to.

 

[LordMustangGT]

run 91 oct allllll the time, what r you thinking.... ask me how I know. even at low boost or stock boost it needs 91. Don't run anything but the best grade you can get at the pump

 

[bud09]

Maybe for a 420A Dodge, 4G37 (1.8L) or the 4G63 NT motor, but not for a turbo motor since the turbo bearings needs the thicker oil since the oil IS the bearing for the turbo shaft and the shaft "floats" while it spins in a film of oil.

Do something thinner and the shaft suffers from skirting into the metal of the turbo frame.

My Ply manual fully states either a 10w30, or a 20w/20 oil in the warm climates. Maybe a 5w/30 in cold climate condition, but that's pushing it.

It's the lower number that we need to pay attention to.

i ran 5w/20 in my NT once, never again. after the 1500mi i started to get lifter tick, changed it out and put 10w/30 having tick only on the first start up of the day for a minute.

 

[VtecvrsTurbo]

10w min weight oils help from getting lifter tick since it's just thick enough to keep pressure in the lifters..5w gets a little thin and the lifters can't operate fully at the reduced pressure of the thinner oils...and these are stock lifters we're talking about.

One drops in 3G lifters and don't even think in using 5w/x oil since the larger opening can't keep the pressure up for needed operation - why the 15w/x to 20w/x oils.

Maybe for a 420A Dodge, 4G37 (1.8L) or the 4G63 NT motor, but not for a turbo motor since the turbo bearings needs the thicker oil since the oil IS the bearing for the turbo shaft and the shaft "floats" while it spins in a film of oil.

Do something thinner and the shaft suffers from skirting into the metal of the turbo frame.

My Ply manual fully states either a 10w30, or a 20w/20 oil in the warm climates. Maybe a 5w/30 in cold climate condition, but that's pushing it.

It's the lower number that we need to pay attention to.

Good god, THANK YOU. Your much better at explaining this than me.

Conclusion: Dont be cheap and run crap gas, and dont use 5w oil.

 

[NHerron]

Holy crap. You mean our engines are some special powerhouse with special needs like none other 4 stroke 4 bangin pos on the road today? Here I was thinking the bone pickin cheap ass prices we pay to get these things moving were a reflection of just that.
Well jeez laa frikin weez glad we got the super mechanics here to save the day. Maybe one day an in depth thread on windshield wiper fluid will surface and an exclusive edumaction on that too will be available. Crossing fingers boys.

 

[1G Eclipse94928]

Holy crap. You mean our engines are some special powerhouse with special needs like none other 4 stroke 4 bangin pos on the road today? Here I was thinking the bone pickin cheap ass prices we pay to get these things moving were a reflection of just that.
Well jeez laa frikin weez glad we got the super mechanics here to save the day. Maybe one day an in depth thread on windshield wiper fluid will surface and an exclusive edumaction on that too will be available. Crossing fingers boys.

Hey no need to get so defensive, you were clearly making stuff up when you said its what the service manual recommends, or have a VERY funny way of reading.

Whats up with all the people who think there stock 4g63 needs a way different oil then what Mitsubishi would run?
Btw Dont bother answering that on this thread because there is a special one dedicated to oil weights...

 

[NHerron]

Weeeeellll then. Call me defensive, I call it the short fuse I have with stubborn asses spreading misinformation. But you're absolutely right. I won't bother, I'll just leave this here.
540RAT - Tech Facts, NOT Myths