tappit noise source

[eaglehawk]

my 01 montana has developed a tappit noise when i first fire it up that usually quiets down after i drive it for a few minutes. sometimes it starts and runs quietly and other times it seems to do it even after its heated up and restarted while running errands. i have heard everything from lifters to a lifter springs. should i be concerned? how can i diagnose without major engine repair? i have gone south for months, up to six, and left it in the garage. lately i have asked my son to come over and start it and drive it occasionally while i am gone. what effect if any does this have?
one morning i fired it up and i heard a metallic pop like something being freed up before it finally quieted down.
update: i added rislone and it quieted down for a while. when it returned i chnged the oil @3000mi and put 10W30 in onstead of 5W30 and it helped a lot. it still ticks at start up but quiets down as it watrms up.

[spike88]

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My wife has a 2003 Buick RDV with 3.4L engine and it "ticks" during first start up as well. Especially during colder weather start ups or when vehicle has been sitting for 5+ days. To reduce the ticking sound (and being hotter summer temp weather), we use thicker #40 engine oil (instead of recommended #30 oil). This thicker oil (only during hotter summer weather days seems to reduce its upper engine ticking noise) seems to help. In all, my wife's Buick's 3.4L engine has been ticking for years. And, its still going strong... (giant smile).

Hope this helps...

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[1999montana]

Two things:

1. I noticed that our van was rattling a bit more than usual in the spring.

2. When I changed the oil, I discovered a small amount of antifreeze in the oil pan that came out as a 'blob' at the end of the drain cycle.

I knew I had a coolant leak, but it was quite minor. On highway use, the engine sounded 'looser' than normal and this fact urged me on to change the oil.

To explain. The engine has always had this ticking lifter or piston slap in the morning. It started at about 30,000 Kms. After about 5 minutes or so, it would go away. I associated this with piston slap due to the design of the piston and a short skirt that causes the piston to rattle in the bore.

From past experience, I've heard sticky hydraulic lifters too, but generally they don't go away since the plunger in the lifter is usually bottomed out and won't return to normal height due to varnish and valve spring loads.

Anyway, I drained the oil in the van as I mentioned. I added Rislone and 10w30 as opposed to 5w30. I figured with 180,000+ Kms, there was sufficient clearance between moving parts and bearings to allow the thicker oil to be used.

Then, I drained some coolant from the rad and added a stop leak additive designed NOT to clog the rad. It sealed a problem with the intake and may have also temporarily sealed a leaky head gasket on cylinder #1.

Why did I do this? The van has already had the LIM gasket repair replaced twice (actually I think my GM dealer only put tabs in the coolant the second time and pocketed the money).

We don't want to spend any more money on it, and I am pretty good at listening to and analyzing the various problems the van has; - fixing them before they become big issues.

Bottom line; - the engine runs smoother, the rattle is gone and there is no evidence of a coolant leak.

So why did I tell you this?

Since you are running a 2001, you may want to investigate whether there is reason to believe that oil and coolant are mixing together. The result could cause the lifter problem you mention.

[eaglehawk]

thanks for your reply. i do have a slow antifreeze leak that i cant seem to isolate and was considering replacing the intake manifold gasket. ive even gotten an oil sample kit to send to a lab for analysis. im still not positive this si the source of my problems.
the results of the lab test are in on 3000 mile oil. high potassium and sodium suggests coolant level of 1.3%. insolubles (sludge) was 1.8% and should be less than 0.6%. the fuel was 2.8% and should be less than 2%. they suggested oil runs of 1000mi until the problem is corrected. i have switched to 10W30 and the tappit nopise is less loud on start up and gets quieter as it warms up. i bought the liquid al stop leak but have not added it yet to radiator.
update: i added rislone and went to 10w30 and it took a few hundred miles but it is running quietly now. im going to have to have some work done on the tranny and will have him look for slow antifreeeze leak. thanks for the oil additive tip it seems to have worked.