Engine issues

[GMFan]

Good evening all,

I've been experiencing a few issues with my 2001 Saturn SL w/ 109,080 miles on it. For the past few months, my engine sometimes will stay stuck @ 2,200rpm idle rather than the normal 800rpm. This happens when I come to a stop but will also happen if I'm coasting with the clutch to the floor. I first figured it was just the throttle position sensor going on me.

However, some folks at saturnfans.com recommended I check for an intake manifold gasket issues (which is a somewhat common failure for the Saturn SOHC of my model year engine).

I finally got a chance to check it out today but like a good BITOGer I checked my oil before I went to get brake cleaner to check for an intake gasket problem.

My oil was 1/2qt low and I noticed white streaks on the stick even though the oil has ~400 miles on it. I don't think it is moisture, because I drove 20 miles highway the night before on my way home from work at 70mph. I wiped the dipstick clean and checked the oil ~8 times with streaks each time. Eventually I didn't get any more white streaks but I suppose I may have disturbed the oil surface in the pan.

I checked my coolant reservoir tank to make sure I wasn't getting oil into the coolant and that I didn't crack my cylinder head. Cylinder head crackings are another issue with these SOHC engines.

Here are some pictures. It started snowing and blowing wind so I didn't get a chance to check my IM gasket.

(Pictures are large in size, but I wanted folks to be able to zoom in and get a closer look.) If you look closely you will notice the white streaks.

Oil
Coolant Resevoir
My cheapest option to check for coolant would be a UOA. However, I used Mobil Clean 5000 two oil changes ago. The oil after that was Formula Shell and now it again has Formula Shell in it. I have heard it takes a few OCI to purge any residual sodium from the add pack of Mobil Clean.

The M.O I am considering is dumping this oil at 3,000 miles, then doing ~1,500 miles on another fill and draining that out for a UOA. I figure after 3 oil changes any sodium would be ridden from the engine.

Let me know what you experts think.

Thanks in advance.

 

[demarpaint]

You can also check for coolant leaks with a cooling system pressure tester. I've tracked down many a leak with one over the years. A UOA won't hurt either, but you will have to wait for the results.

 

[c502cid]

Couple of fine internet guesses here.
1) Both times I had a sticking high idle like that, the throttle plate was dirty. Cleaning it up fixed it quick.
2)Forget the overflow, can you look under the radiator cap? Does it have one?
Just guessin'......

 

[mpvue]

I worked on a friend's SC1 w/ a high idle; it was the throttle body gasket. I would check the PCV hose also. my experience is those are the 2 most prone places.

 

[GMFan]

Thanks for the replies.

I cleaned the throttle body at 100,000 miles. It had a little carbon buildup but nothing major.

I don't think this car has a radiator cap.

I still believe the high idle rpm issues is due to a failing Throttle Position sensor. I believe it is most likely a separate issue than the possible coolant leak.

 

[Bill in Utah]

The cap on the tank is a "radiator" cap. It holds pressure.

The dipstick looks ok. The slight foam in the tank could just be moisture (not coolant).

Change the oil, keep a eye on it and once you get 1500-2000 miles get a UOA. If anything worsens, then change the plan...

As far as high idle... I think you Throttle position could be a problem. Throwing any lights/codes?

Bill

 

[GMFan]

Bill,

Would it be safe to assume that a UOA on the third oil fill since using a Mobil oil would be clear of any leftover sodium? If I recall, it took you 3 oil changes before the sodium was gone after using an oil with a sodium in the add pack?

I want to be sure that when I get the UOA I won't get a low sodium number and second guess if it is from the oil or if I am getting coolant mixed in.

 

[dishdude]

Have you changed the coolant temp sensor yet?

 

[eljefino]

TPS issues clear up with a shutdown/restart. The thing autozeroes every time the car "boots".

I think your oil and coolant are fine. Though the coolant probably needs changing.

You can also get a cyl 1 misfire when your IM gasket gets bad enough. I did that gasket on my y2k and it looked like the factory one was jammed in there wrinkled by an uncaring robot.

 

[Bill in Utah]

Originally Posted By: GMFan
Bill,

Would it be safe to assume that a UOA on the third oil fill since using a Mobil oil would be clear of any leftover sodium? If I recall, it took you 3 oil changes before the sodium was gone after using an oil with a sodium in the add pack?

I want to be sure that when I get the UOA I won't get a low sodium number and second guess if it is from the oil or if I am getting coolant mixed in.


I still think it WILL show some sodium but not enough to mask a coolant leak.

I'd want to know sooner than later.

take care, bill

 

[GMFan]

Originally Posted By: dishdude
Have you changed the coolant temp sensor yet?


Yes, the ECTS was changed around 100,000 miles.

Originally Posted By: eljefino
TPS issues clear up with a shutdown/restart. The thing autozeroes every time the car "boots".

I think your oil and coolant are fine. Though the coolant probably needs changing.

You can also get a cyl 1 misfire when your IM gasket gets bad enough. I did that gasket on my y2k and it looked like the factory one was jammed in there wrinkled by an uncaring robot.


Original coolant was changed at 88,000 miles.

Originally Posted By: Bill in Utah
Originally Posted By: GMFan
Bill,

Would it be safe to assume that a UOA on the third oil fill since using a Mobil oil would be clear of any leftover sodium? If I recall, it took you 3 oil changes before the sodium was gone after using an oil with a sodium in the add pack?

I want to be sure that when I get the UOA I won't get a low sodium number and second guess if it is from the oil or if I am getting coolant mixed in.


I still think it WILL show some sodium but not enough to mask a coolant leak.

I'd want to know sooner than later.

take care, bill


Thanks Bill, I will keep an eye on my coolant level. I plan on getting a UOA on the next oil I install.

 

[benjamming]

I would get a UOA on your current oil at 3k miles.
What coolant are you using?
A good analyst (ahem, Terry) will be able to tell if there is a coolant leak despite previous oil used as long as you give him the maintenance history.

 

[GMFan]

Originally Posted By: benjamming
I would get a UOA on your current oil at 3k miles.
What coolant are you using?
A good analyst (ahem, Terry) will be able to tell if there is a coolant leak despite previous oil used as long as you give him the maintenance history.


I'm not 100% sure, because the previous owner had the coolant changed at a shop. I got the car shortly after. I'm assuming the shop used the GM dexcool as specified in the owner's manual since it is orange (I once dipped a paper towel into the reservoir and it came out orange.)

I topped it off two summers ago soon after I got the car with a small cup of coolant. I used Prestone Dexcool for GM vehicles. I haven't had to add any coolant since.

 

[mechanicx]

Just to correct something, the TPS doesn't control idle speed, but the IAC valve does if that's what you meant. I would check for a vaccuum leak first. I think you might have signs of a headgasket leak or a crack head, but hard to tell from the pics. I think it was Demarpaint suggestion to run a coolant pressure test was right on. This situation points out why I don't like oils that contain much sodium.

 

[BuzzCut]

That is an IAC that makes them idle high like that. TPS wont do that unless it has been played with normally. With the high miles the IAC might just need to be cleaned but replacement would be better.


Originally Posted By: GMFan
Thanks for the replies.

I cleaned the throttle body at 100,000 miles. It had a little carbon buildup but nothing major.

I don't think this car has a radiator cap.

I still believe the high idle rpm issues is due to a failing Throttle Position sensor. I believe it is most likely a separate issue than the possible coolant leak.

 

[demarpaint]

Originally Posted By: mechanicx
Just to correct something, the TPS doesn't control idle speed, but the IAC valve does if that's what you meant. I would check for a vaccuum leak first. I think you might have signs of a headgasket leak or a crack head, but hard to tell from the pics. I think it was Demarpaint suggestion to run a coolant pressure test was right on. This situation points out why I don't like oils that contain much sodium.


Thanks for the compliment, that pressure tester has proven its worth over the years many times over finding annoying coolant leaks.

 

[river_rat]

Drop a drop or two of the streaky oil on the hot exhaust manifold and see if it crackles and pops. ( = moisture)

 

[demarpaint]

Originally Posted By: river_rat
Drop a drop or two of the streaky oil on the hot exhaust manifold and see if it crackles and pops. ( = moisture)


Now there's an old trick.

 

[onion]

Originally Posted By: river_rat
Drop a drop or two of the streaky oil on the hot exhaust manifold and see if it crackles and pops. ( = moisture)


That's a [censored] good idea. I'm gonna try that next chance I get.

 

[GMFan]

Thanks for the replies.

The good folks over at saturnfans.com said it could be the TPS since the idle would go back to normal if I shut the engine off and turned it back on (sorry I forgot to mention that in my original post). They said an AIC would be constant and an engine cycle wouldn't fix the rpm issue.

Let me know if this sounds accurate.

I will admit that I haven't tried it too often (power cycling the engine when I got the high rpms). I will say that when the car would idle high, it would stay that way the whole time until I got to my destination. I was usually too worried to cut the engine off at a traffic light in case it wouldn't start again.

Another thing is that the high rpm idle issue seems to have happened on the colder mornings. It seems to have gotten more consistent as it has gotten colder outside. I haven't experience a high idle on start up. Usually it starts 10 minutes into a drive. I therefore can't really say if the issue is temperature related or just an issue that is making itself more prevalent. (i.e. headgasket etc)

Head crack would be bad news. The vehicle is worth just under $2,000. Not sure if replacing the head would be cost worthy. However, most folks who get cracked heads get nasty milkshakes in their coolant reservoir. Mine looks nothing like a cracked head right now. Time will tell.

Thanks again.