re-surfacing a 2002 SL1 head

[GSDrew]

Should an SL1 head be dis-assembled and resurfaced when changing the head gasket?
My 2002 SL1 is now leaking water so bad the system will not pressurize. The head gasket does not seem to be blown to the cylinders because there is no misfire and it idles as smooth as ever. Also, the oil seems to be water free.
TIA

[OldNuc]

No and if you would like to skip the gasket replacement try this and ONLY this, follow directions exactly. You can sometimes find this at local parts store.
https://www.amazon.com/Bars-Leaks-HD...rds=BARS+leaks

No more than 2 tablets and crush them up before dumping into reservoir.

[billr]

So... where does the water end up when you try to pressurize, on the ground? If it's not in the oil or cylinders, then that seems where it would have to be, and you could see where it is coming from.

Point is, are you sure this isn't a leak from a hose, radiator, water-pump, etc? Isn't '02 in the era where they had the coolant leaks in plastic intake manifolds?

[OldNuc]

leaks from where they always leak.

[fetchitfido]

Originally Posted by billr

Isn't '02 in the era where they had the coolant leaks in plastic intake manifolds?

'00-'02 DOHC's have plastic intake manifolds. '91-'99 DOHC's and '95-'02 SOHC's have the same aluminum intake manifold (minor changes to how the fuel rail mounts year to year making swapping more interesting than it should be). '91-'94 SOHC's also have aluminum intake manifolds but they're incompatible with DOHC's and '95+ SOHC's.

Generally SOHC's crack the heads rather than blow the head gasket, unless there's a visual issue with the HG when you take it off have the head checked for cracks and focus around #2 cam journal.

[OldNuc]

Head gaskets seeping water are quite common. Easily fixed with the product recommended. OEM Saturn used it for years in every car off the line but the factory coolant fill is long gone now and along with it the OEM approved leak stop, so now you get to reinvent the wheel and find out what Saturn put it in there for. After GM took complete control of Saturn they terminated adding it at the factory --GM orders.

[pierrot]

Originally Posted by GSDrew

Should an SL1 head be dis-assembled and resurfaced when changing the head gasket?......
TIA

In general, checking a cylinder head surface for warpage is well worth doing once it's off of the engine, even if it confirms that all is in order. Not knowing about the S-Series cylinder heads, it is true that there are heads which do not require disassembly prior to resurfacing. I would think that a well trained machinist could check for warpage on your cylinder head without having it disassembled.

[GSDrew]

Sorry for the lack of response on this thread, been very busy getting ready for Christmas time off.
Anyway, it all started when I bought this car over the summer with a very bad intake intake leak on #1 & #2 cylinders and a very small radiator leak among other small issues.
I replaced the intake gasket (BTW the intake is not plastic) and the radiator. 2.5K miles later water was leaking on the backside of the engine at #4. I thought the new Felpro intake gasket had failed, so I replaced it a second time and the water continued to leak.
Chatted with OldNuc (Thank you), concluded it was a leaky head-gasket and decided to try the Bar's tablets (x2) approach. The first day after 20 miles there was no leak. Cool! Problem solved, next problem.
Day two... more leaks so I added 2 more tablets, pre-crushed, that evening. I also noticed water had pooled in the small recessed square on the front corner of the block at #4. I also saw dried coolant below it and on the trans. The only way for coolant to get there is by leaking out the opposite side of #4. The second set of tablets seemed to work, no noticeable steam but it leaked the next morning on the way to work again. Two more tablets that evening, drove it around a little and it continued to leak, it didn't even slow it down. As I was refilling the water it was leaking out on to the ground (like rain) on the back side of the block, at #4, and trans.
There is no doubt in my mind the head-gasket is gone. Luckily I'm not seeing the typical milk-shake oil in the cap or dip-stick. I'm going to do a compression test later today but I'm pretty sure that will not show any head-gasket compression issues because it does idle smoothly.
So, thanks for answering my question about not tearing down the head to resurface it.
I'm now waiting for parts gaskets and head bolts to arrive from Rockauto.

[GSDrew]

I warmed the engine up to about half way to normal operating temp , unplugged the fuel pump relay and measured the compression:
#1 120 PSI
#2 115 "
#3 112 "
#4 115 "

This engine has supposedly 87K on it so that seems about right... I guess.
And there's no water in the oil.

[billr]

As you have found out, those tablets are useful on some type of leaks, and useless with others. When you said it wouldn't hold well enough to even pressure test, it was a big hint that this wasn't going to be corrected by the tablets. Coupling the visible external coolant leakage with poor compression and it seems certain the head will have to come off.

In regards to your original question: get the head checked for flatness, along with the block. Head gaskets on a stock-type engine rarely (never?) fail from just age.

[OldNuc]

Originally Posted by GSDrew

I warmed the engine up to about half way to normal operating temp , unplugged the fuel pump relay and measured the compression:
#1 120 PSI
#2 115 "
#3 112 "
#4 115 "

This engine has supposedly 87K on it so that seems about right... I guess.
And there's no water in the oil.

You screwed up the compression test but since the engine actually runs your compression is at lest 150.

Run the compression test THIS way and do not screw the tester in to the point you squash the o-ring, stop just at the point of contact or it leaks.

To prevent washing the cylinders down with fuel remove the PCM B fuse to shut off the fuel pump, injectors, and ignition before starting the test. Remove all spark plugs and block the throttle open. Use a low charge rate battery charger to fully charge the battery before conducting the test.

Crank the engine until the gauge quits increasing and compare both the final pressure and number of compression strokes to reach the max pressure, cylinder to cylinder. You can do this test either cold or hot or warm just mention it when stating results.

For example if you find all cylinders produce a final reading of 200psi but the compression cycles are as follows: 1-8, 2-6, 3-8, 4-14 then it should be obvious that cylinder #4 has a serious problem with leakage past either the valves or compression rings.

FSM states the MINIMUM number of compression cycles is 10 and a Fully charged battery is required to obtain the full 250RPM cranking speed.

Nominal compression for a high mileage good condition DOHC is 190-220psi and SOHC is 175-205psi.


Pulling the head based on your numbers would be incredibly stupid and expensive.

Based on the continued leakage a new head gasket is required but you can check the head condition with a plain old carpenters square. Google has pictures and it is simple to do. You have NO SIGNS of a compression leak to the outside. A compression leak into the coolant will be obvious when the head is off and you can inspect the old gasket.

[OldNuc]

Warped heads on the S-Series engine are extremely rare and usually accompanied with obvious signs of repeated overheating. Head gasket rot caused by coolant soaking is quite common.

[GSDrew]

OK... I was thinking the compression was a bit low, but I don't know what this SL1 should be. I was basing my conclusion on the range between cylinders, 8 PSI from min to max I consider pretty good.

My procedure was as follows:
Remove the fuel pump relay
Put large screwdriver in the throttle-body butterfly
Remove plugs
Attach compression gauge to #1 and crank 12-15 cycles
Read gauge
Repeat for the other 3 cylinders

I wasn't able to see the gauge during the test but from past experience I expected the pressure to have already hit max.
I didn't use a battery charger since the engine seemed to spin fast enough and I didn't watch the revs.

If anything I think I may have attached the hose too tight because I did tighten it as much as I could by hand. I never had this problem before when I used a nice Snap-on tester. However, this is a new and cheap one from Harbor freight and the gauge may be off.

Sorry but you'll need to explain to me one point of your procedure. What does the -8, -6, -8 & -14 mean in "1-8, 2-6, 3-8, 4-14"? I assume the 1, 2, 3 & 4 are the cylinders.

Will try it again with my battery charger, will also remove the PCMB fuse, assuming it is labeled as such. Time to get the book out.
Thanks again.

[fetchitfido]

Originally Posted by GSDrew

Sorry but you'll need to explain to me one point of your procedure. What does the -8, -6, -8 & -14 mean in "1-8, 2-6, 3-8, 4-14"? I assume the 1, 2, 3 & 4 are the cylinders.

How many cranks it took that cylinder to reach it's highest compression point.
1-8
cylinder-cycles


A healthy cylinder/battery/starter will reach 200-210psi under 5 cycles, we've had reports of an evenly worn motor still starting down to about 130psi but if 3 are at 150psi and the 4th is under 100psi they generally won't run. According to the FSM it's time for a rebuild under 180psi.

[billr]

^^^ +1

If 4-5 compression strokes doesn't get it up past 180 psi, you have a sick hole. Even if the throttle isn't blocked open it should get well past 150.

Having the same compression on all cylinders is desirable, but having them all the same at a low number is not...

[OldNuc]

These are well used engines and contrary to your theory they run relatively well with 1/3 of an exhaust valve missing and only a poor idle as the symptom.

[OldNuc]

Originally Posted by GSDrew

OK... I was thinking the compression was a bit low, but I don't know what this SL1 should be. I was basing my conclusion on the range between cylinders, 8 PSI from min to max I consider pretty good.

My procedure was as follows:
Remove the fuel pump relay
Put large screwdriver in the throttle-body butterfly
Remove plugs
Attach compression gauge to #1 and crank 12-15 cycles
Read gauge
Repeat for the other 3 cylinders

I wasn't able to see the gauge during the test but from past experience I expected the pressure to have already hit max.
I didn't use a battery charger since the engine seemed to spin fast enough and I didn't watch the revs.

If anything I think I may have attached the hose too tight because I did tighten it as much as I could by hand. I never had this problem before when I used a nice Snap-on tester. However, this is a new and cheap one from Harbor freight and the gauge may be off.

Sorry but you'll need to explain to me one point of your procedure. What does the -8, -6, -8 & -14 mean in "1-8, 2-6, 3-8, 4-14"? I assume the 1, 2, 3 & 4 are the cylinders.

Will try it again with my battery charger, will also remove the PCMB fuse, assuming it is labeled as such. Time to get the book out.
Thanks again.

The numbers are the number of compression strokes for each cylinder to reach a stable max pressure. You should see 180-205psi peak for your engine and what 5 strokes produces is of absolutely no value at this point in your exercise. The PCM B fuse is in the engine compartment fuse box and the locator diagram is in the inside of the cover. Charge the battery overnight before running this test and it can be run cold, temperature will have minimal impact on readings.

[GSDrew]

I reran the compression test with oil and the compression did rise to 135 to 145 PSI, still not even close to what everyone says is normal.
So... I still going to do the headgasket, get the car running as nice as it was before and then sell it.
I kinda knew that the mileage on this car was just too good to be true, especially after I started digging into the car and finding things that just didn't add up to a low mileage car.
I'm also going to take my compression test gauge into work and compare it to a calibrated gauge. Hopefully, I'll find it off by 50 PSI but I doubt it. Even cheap Chinese gauges shouldn't be off by that much new out of the box.
Thanks for your help guys

[OldNuc]

If the o-ring is old and cut up it leaks and you get low numbers. If the starter/battery are weak you get low numbers. If the engine starts easily and idles smoothly the odds are very good that the compression is fine as at 150psi they are very weak and doggy. If you have an automatic they run very bad that low --no power. If you pull the head and then find the ridge at the top of the cylinder is deep enough to easily snag a fingernail on then you might suspect that those numbers are close to correct. Compression numbers have no direct relationship to oil burning but if that engine is not an oil burner then those compression numbers are highly suspect.

[1996SL11.9L]

My resurfaced head on the 96 SL1 still pushed coolant out at cylinder #4 which is why I pulled the head in the first place. My engine guy warned me that it could come back.

I used the copper glitter stop leak. Which healed the leak at the head block junction until it got wrecked 40,000 miles later.

While the head was off I did the Singhs grove to the combustion chambers and did the surface tension mod to the back side of the intake valves. Shame that head won't fit in my 2002.