Lifter noise (cold) and misfire code 301

My daughters 96 Lesabre-custom, 115,000 miles, 3.8L.
I got a code 301 misfire so I figured its time for a tune up. I replaced with AC delco plugs-OE-7 dollars each and AC delco wires. Seemed to run ok for about a week then when the car was started cold, 20F deg, and it appeared to have a loud lifter noise and I got the 301 code again. Today replaced the oil filter (fram 3387A) and oil (10w30) and used oil additive Lucas oil stablizer. I generally do not use these products but (what the H). I hear so much of the UIM problems so I pressure checked 15psi the coolant system. It lost about 1/2 lb pressure in 15 minutes. Is that OK? The oil was dirty and no foaming or milky substance. You might be thinking why is he checking the coolant system, cause when I add coolant to the bottle it is gone within a week. So I checked the system, hoses and bottle. I was thinking could coolant leaking around the lifters and cause them to stick?
So any ideas of what is causing the lifter noise?
Also I was thinking of flushing and replacing with the green antifreeze.

thx

The coolant loss is an issue for sure, the pressure test really may not help here. The 301, is it accompanied by a noticeable miss? Either way on this car I would do an uim as it will fail at some point anyway. Yes coolant contaminated oil could affect the lifters. What did the #1 plug look like compared to the rest?

Yes coolant contaminated oil could affect the lifters.

I'll second that.

It doesn't take much coolant contamination to cause lifter noise or a rattling sound at cold start. You may not see it visually but an oil analysis will probably confirm it. Unless there is external leaking that much coolant loss indicates an issue with either the UIM Plenum, UIM gaskets or the LIM gaskets. Probably causing the misfire DTC too. I would not wait too long for a top end tear down at least to the LIM level. The coolant will damage other engine parts like the cam, crank and connecting rod bearings or cause a hydro-lock.

Thx for the reply.
I think the UIM was done but not sure I just bought the car for my daughter. No coolant in the oil or trans fluid. Nothing mixing between the oils. It does look like someone mixed the anti-freezes green and orange. I was thinking of a test, bring the engine to operating temp, attach the pressure tester and see if pressure increases. If it does, I will keep resetting the pressure gauge to zero. The idea, if the combustion gases are getting into the coolant then the cooling system will continue to increase in pressure.
Oh by the way no coolant in the brake fluid either,,,,just kidding!!!

thx
R

I drained the Lucas oil last night and replaced the oil with AC delco filter and marvel mystery oil (1 qt). Lifter noise is already gone. I will post back in a week or so.
Thats it for me on auto parts. AC Delco is it. For years I have change parts and it does not work as expected then I second guess myself, is the part is as good as OEM. No more guessing, AC Delco for me.

R

The AC delco filters are good and have the anti drain back valve in them. Plus you can pick them up cheap for like $3.49

The OEM upper intake manifold is stamped in two corners with (hidden bolt)
I have not seen this on replacement manifolds
I would change the UIM as an insurance policy if it has not been already.
If you are losing a cup or two of coolant a week that is too much IMHO.

I wouldn/t leave the MM oil in there permanently, it is not designed as a long term lubricant.

Could the coolant be leaking somewhere at an elbow or a water pump?

Did the deterioration of gaskets and EGR tubes through the upper intake manifolds start with 1996?

I drained the Lucas oil last night and replaced the oil with AC delco filter and marvel mystery oil (1 qt). Lifter noise is already gone. I will post back in a week or so.
Thats it for me on auto parts. AC Delco is it. For years I have change parts and it does not work as expected then I second guess myself, is the part is as good as OEM. No more guessing, AC Delco for me.

R

hey ralph you put toooo much marvel mystrey oil in that engine....you got to change that oil ...only put 4 oz. max into the engine oil...and when the oil gets black you must change oil...this product works but running the engine with all that marvel you will wear the internal componets out

Did the deterioration of gaskets and EGR tubes through the upper intake manifolds start with 1996?

As far as LeSabre if it has the VIN "K" but it is applicable to all '95-'98 GM cars with the Series II 3800 engine as far as the EGR stovepipe meltdown issue and substandard UIM and LIM gaskets. For '99 and up EGR stovepipe issues are less common but not uncommon for the UIM or LIM gaskets.

The web sites say 1qt of MMO in the crankcase. In this car I may not have to drain and refill cause there is an oil leak somewhere and I am adding oil monthly. On a side note, why does the OEM put the oil pressure gauge on the pre-filter side of the oil filter. The true pressure to be monitored is the oil pressure within the engine not the pressure before the oil filter. A clogged filter will still show good pressure.

thx

I dont think so. That is why I pressure tested the cooling system cause it would show up right away.

After my 1999 LeSabre UIM let go and it hydro-locked the engine in my driveway (I was lucky there) I did the repair myself and did an oil change and filter. 500 miles later I did an additional oil change and filter and did the Z-Max treatment to the motor oil and transmission. Even my wife swears the car runs smooth and like new again.

There were two holes that in the UIM where the stove pipe (about the size of BBs) goes were too big for bar leaks to plug up (dont ask me how I know this - heh)

I think my 1999 is an early model because the stovepipe was bigger than the one I checked on my 2002. I did replace it with a smaller one that came with my new UIM from ineedparts.com

On a side note, why does the OEM put the oil pressure gauge on the pre-filter side of the oil filter. The true pressure to be monitored is the oil pressure within the engine not the pressure before the oil filter. A clogged filter will still show good pressure.

thx

The oil filter will be bypassed by the motor's bypass valve if the filter generates pressure above that amount which may be in the 60 psi range. The filter also has an internal bypass which likely is operating part of the time with cold oil or when the filter media is loaded with particulate.