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Discussion Starter #1
Hi guys,

I've been chasing and fixing all kinds of problems on my 180k mile 94 9c1 but i figured this is probably big enough to ask for some help.

I recently did my opti and waterpump and yesterday I noticed some steam coming from the overflow tank cap. I immediately (after finding a thick leather glove) screwed the cap down really tight and steam was still slowly coming out. I also heard a bubbling sound but there is typically some bubbling or pressurized gas leaking sound whenever I turn off the car and I thought this was normal and never noticed steam other than one time whem the tank boiled over. Should steam be coming out or should everything be sealed up? Also is there really no rad cap or is my radiator not the original style? The gauge did go up to 1/2 for a bit just before I shut the car off and it usually sits between 1/8 to 1/3.

Before I replaced the coolant temp sensor in the water pump (did this prior to opti and wp) the system overflowed (and over heated) when attempting to clean the throttle plate and engine using seafoam spray. This was the only time the engine over heated since I have owned it (5k miles or so) and it was because the fans never came on presumably due to a faulty sensor in the water pump.

My initial guess was I have a bubble but I already bled the air. I haven't bled since the initial bleed I did after the opti and wp swap, but I did it 3 times and the second time had no air from the beginning. Third time was just for fun lol.

Does this mean my head gasket is shot? When I first bought the car I noticed some water in the valve cover (white gunky residue) on the passenger side. I figured it was just from sitting for a long time and getting condensation but now I'm thinking it's the head gasket. Any way to verify this and is there any easy fix or even a band aid that will get me through another oil change or two? I will be able to do a rebuild once I move in the next 6 months or so (I don't drive much).

Also the motor often makes a pretty rough (kind of like a metal to metal contact) sound when starting. Sounds a bit like when an engine runs out of gas but only for a second. Not sure if it's related or not.

Otherwise the engine runs super strong and never overheats but has a rear main or oil filter adapter leak.

Thanks everyone!
 

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Can you have the cooling system and cap pressure tested? Caps can fail, overflow tanks can crack, etc.
You can take an oil sample and send it to Blackstone Labs in Fort Wayne, IN. Their report will tell you how much coolant contamination you have in the oil.
Condensation will collect in the oil fill tube, it is not necessarily an indication of a blown head gasket.
The noise on starting could be a poorly fitted starter, some require shimming to get the clearance correct, or the flexplate could be cracked.
Most common location for an oil leak is the rear of the intake manifold, second is the oil filter adapter. FelPro gaskets fix either or both.

Ken
 

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Steam?

When you swapped out your water pump, assuming it is a stock pump, did you take the 'gear sleeve' off of the old pump and put it on the new pump? I had a tech change my pump and he could not figure out why the engine temp went up, and the heater would not get hot, until he looked at the old pump and said, "****'.
 

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Discussion Starter #5
When you swapped out your water pump, assuming it is a stock pump, did you take the 'gear sleeve' off of the old pump and put it on the new pump? I had a tech change my pump and he could not figure out why the engine temp went up, and the heater would not get hot, until he looked at the old pump and said, "****'.
I almost did that! Fortunately I caught it 5 min after bolting the pump on and before trying anything so the gasket sealer was still tacky and I was able to get it in easily without issues. My heat does work and the car doesn't over heat. Never been past the middle of the dash gauge anyways.
 

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Discussion Starter #6
Can you have the cooling system and cap pressure tested? Caps can fail, overflow tanks can crack, etc.
You can take an oil sample and send it to Blackstone Labs in Fort Wayne, IN. Their report will tell you how much coolant contamination you have in the oil.
Condensation will collect in the oil fill tube, it is not necessarily an indication of a blown head gasket.
The noise on starting could be a poorly fitted starter, some require shimming to get the clearance correct, or the flexplate could be cracked.
Most common location for an oil leak is the rear of the intake manifold, second is the oil filter adapter. FelPro gaskets fix either or both.

Ken
I can probably get the system tested but I'll probably just get a new cap since it is probably that. It only vents steam whem the engine is near mid way on the gauge and only from the cap. I'll send in an oil sample at my next oil change and see whats up.

Even before I put in the new starter the engine made this noise. It sounds like lifter noise maybe but only for a second and not every time it starts but maybe 70% of the time. I cant recall if its worse with engine warm or cold but I think it's worse when the engine is warm. I didn't inspect the flex plate but wouldn't that contribute to a continuous noise?

I'm still hunting this leak. I think its my rear mains or the oil the oil filtet adapter. But im still struggling to get the back of the motor clean to fully verify its not the intake.

Thank you so much!
 

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Discussion Starter #7
It is not an overflow tank. It is a reservoir and a cap that are part of the pressurized system.

Think of it as an extension of the radiator.

Your cap may be bad. If original - get a new GM part.

https://www.amazon.com/gp/product/B000C9SMC2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Have you tested your thermostat? Rent a pressure tester and test the whole system.

https://www.amazon.com/ACDelco-131-100-Original-Equipment-Thermostat/dp/B000C982F4/ref=pd_bxgy_263_2/146-4224982-5105528?
I have not tested my tstat. How do I do this? I know its relatively new and I was told by previous owner it was a "low temp" tstat. I have the box for it somewhere. My guess is its a 160 or 180.

I'll try a new cap anyways as mine is pretty dingy and has some strange brown stain I can't get off.

Haven't seen steam in a while but still making the same strange sounds at shutdown. Not so much a boiling sound but similar to pouring water on a fire pit only much quieter.

Thanks for the info!
 

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Discussion Starter #8
On follow up. I topped off the coolant and tightened the old cap really good but steam still comes out from around the cap. As far as I can tell its steaming only around the cap and with it tightened really well it makes a bit of a hiss. Upon shutting off the engine the engine makes some bubbling noises as is has since I've owned it. Gonna try the new cap tomorrow.

Checked the tstat box there was actually one in it which looked new! So the one i have might be the original. The box is a 160 hypertech. I reused the tstat that was in the old wp when I did my opti and wp recently. If I knew there was tstat in that box I would have used that one although i really dont know what it is. It might not be what the box says
 

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I have not tested my tstat. How do I do this? ......
It, and a candy thermometer in a pot of water heated on the stove.

I'll try a new cap anyways as mine is pretty dingy and has some strange brown stain I can't get off.
It's a maint. item. So yah sounds WAY overdue to simply replace lol

Haven't seen steam in a while but still making the same strange sounds at shutdown. Not so much a boiling sound but similar to pouring water on a fire pit only much quieter.

Thanks for the info!
Confirm for everyone you ain't just hearing air hiss back out of the intake - for like 3/4 second.

And BTW listen to Ken- up there for much the much more likely causes of a leak than the rear main.
 

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Discussion Starter #10
It, and a candy thermometer in a pot of water heated on the stove.

It's a maint. item. So yah sounds WAY overdue to simply replace lol

Confirm for everyone you ain't just hearing air hiss back out of the intake - for like 3/4 second.

And BTW listen to Ken- up there for much the much more likely causes of a leak than the rear main.
Wonder if my ir thermometer would work. I'll try this with the extra tstat I found yesterday.

I can confirm the hiss is not from the intake and it persists for quite a while after the engine stops running.

As for the leak it's gotten worse after doing some cleaning around the rear mains and oil filter adapter. I hope it's thr oil filter adapter though and not the mains.

This forum rules, thank youso much!
 

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Discussion Starter #11
New cap seems to do the trick. However, the car is running super cold now. Less than 1/4 on the gauge since swapping the cap. Guess this is not a bad problem to have though?

Comparing the new and old cap it seems the old cap was missing a gasket! There are some ridges that I thought were the gasket but the new cap clearly has a thick rubber gasket. I didn't tighten it nearly as tight and it seems to be working great.

Now I gotta find this oil leak. Did I mention it got worse since cleaning (really just spraying with gas and awesome from the dollar tree to degrease) around the oil filter adapter and rear mains. I dont really understand how to clean the backside of the intake since I cant even see it. But from what I can see it looks MUCH cleaner than the rear mains and oil filter adapter locations but they were extremely covered in grease and grime. I added half a quart of heavy duty oil stabilizer (Walmart brand since they were out of Lucas) since it was a bit low on oil, hoping this will slow the leak some. Gonna do some more cleaning today hopefully after the boat races
 

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...... I pulled the trans to do the repair and found the leak was from the oil filter adapter. If I had found that first life would have been so much easier. .....https://www.impalassforum.com/vBulletin/34-engine-problems-maintenance/254953-cant-get-oil-filter-adapter-off.html

Mark: Snowman-33

The gods of good karma were blessing you and here you missed a golden opportunity for all manner of 'safety upgrades' to that tranny: added sprags this and increased frictions and steels that, and Sunbeast shell here and hardened input shaft there, and something about alto or red band IDR, and then there's all the valve body mods. And well of course the new converter. Funny, my 40k tranny flat out died 3 days after getting it back from repair after a rear-ender. My insurance co. was very happy paying me $900 for parts to rebuild it myself v. ~$2,500 for a shop to put a rebuild in. It took me 3 months but I had a lot of fun getting all the goodies in. The Tran-Go kit VCR, FSM and ATSG manuals became my best friends. lol
 

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The gods of good karma were blessing you and here you missed a golden opportunity for all manner of 'safety upgrades' to that tranny: added sprags this and increased frictions and steels that, and Sunbeast shell here and hardened input shaft there, and something about alto or red band IDR, and then there's all the valve body mods. And well of course the new converter. Funny, my 40k tranny flat out died 3 days after getting it back from repair after a rear-ender. My insurance co. was very happy paying me $900 for parts to rebuild it myself v. ~$2,500 for a shop to put a rebuild in. It took me 3 months but I had a lot of fun getting all the goodies in. The Tran-Go kit VCR, FSM and ATSG manuals became my best friends. lol
Bob, that was before I lernt about B Bodys. Right now the tranny is on the patio next to the rear. I started to shotgun buying parts for the entire car. I have boxes with AN hose and fittings, interior parts, body parts steering/ suspension plus lots more. Now I'm trying to concentrate on the frame and suspension. The engine is on the stand but I ran out of room in the garage to really get it all together right now. You built you trans? Hmmmm I can come there with brew & seegars. (If I remember correctly) I have the FSM and ATSG already and some parts.

Mark: Snowman-33
 

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New cap seems to do the trick. ......

Periodic maint. to the rescue - as always! ;) Glad you beat that one to submission. The aril leak is pretty much meh, but'll show ya 3 more maint. things to attend to. lol



..... You built you trans? Hmmmm I can come there with brew & seegars. .....
Mark: Snowman-33

Yep. Every step redone at least 4x, some done just one more time from the opposite side of the plywood table to be sure. I don't be pounding down the spirits near as earnestly as years back. But we'll get a kick outta those seegars and that VCR running on 7.1 Atmos eh.
 

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Discussion Starter #17
This might be a little helpful. I thought I had a rear main leak. Oil was dripping from the hole in the converter cover. I pulled the trans to do the repair and found the leak was from the oil filter adapter. If I had found that first life would have been so much easier. Hopefully you have the same minor problem. Check this out for more info. https://www.impalassforum.com/vBulletin/34-engine-problems-maintenance/254953-cant-get-oil-filter-adapter-off.html

Mark: Snowman-33
Thanks for sending this! I read both threads but I'm still confused as to what gaskets to get for the oil filter adapter.

I went to firestone today (to have my ac checked, new compressor leaks, ugh)
and they checked the car for leaks and said for sure the oil filter adapter is leaking, but possibly the rear mains also.

Gonna do the adapter next oil change but I want to make sure I get the right gaskets. I'd like to replace the oil cooler gaskets as well but cant find these part numbers either.

Hopefully my oil pressure goes up like another member mentioned after they changed their filter adapter gaskets 🙂
 

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https://www.gmpartsdirect.com/oem-parts/gm-s-gasket-kit-88893990

Any decent GM dealer will have this common part in stock. Otherwise, order on line.
Thanks! Picked it up last night. Probably will do my oil in the next few fuel ups and will install this then.

Is there any reason to do the cooler line gaskets if they arent leaking?

Next task is my AC system (again) and shocks. Anyone known what shocks to use with belltech drop spindles in the front and lowering springs in the rear. Not sure how low it is but the rear seems lower than the front and the rear springs fall out when lifting the car (whats the best way to prevent this?). I want Monroe shocks because of the lifetime warranty but not sure if any will work.

For the AC system, how much oil do I use and where do I pour it in? Im going to replace the compressor, drier and orifice tube. I did the condenser last time even though I dont think it was necessary as no metal shavings came out of the old one. Are their orings on the ends of the lines that go into the compressor or just the metal shrouded gasket? I already did this once but I forget what I did. Also, is there any way to prevent the compressor from failing again? Apparently its leaking out the back side between the front and rear sections of the compressor itself. A mechanic told me I need a "high temp" orfice tube to keep the pressure in the back of the compressor as low as possible during high heat days but I can't seem to find this part.
 
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