Oil 5w30 or 10w30
 

about 3 weeks ago I changed the oil on my old blazer (134,000). thinking that the old beast having that many miles on it I added the Lucas oil treatment to it and changed to 10w30 now I have less piston slap but now have a lifter tapping. I think I read somewhere on here that thicker oil helps the lower end but not the top end. it ls sound like the lifter is on #3 cylinder, not knowing the oil path but guessing #3 must be closer to the end. years ago we used to add about a cup of transmission fluid to the warm motor and run it for about 30 minutes then changed the oil, and that would normally flush out the lifters. will that hurt these newer motors, would it help the noisy lifter. if so is the 10w30 and Lucas to much for this old motor should I go back to the 5w30 straight and should I put Lucas back in the oil?

I cant see how it will make a difference in this season.
Lifter tap reflects the engine's lube history. The lifter tap is likely due to deposits built up and now shifted. That's why the trans fluid work sometimes. Use of poor quality oil and too long between changes.
But every situation is different and who knows what will work.

Is the lifter tapping all the time or just on startup? There's a big difference in how to react to it.

it taps about all the time more in the morning but after it warms up it not as bad but taps all the time to some degree. the warmer it is the less it taps. I drove it about 60 miles Saturday (about 70 deg.) anytime you came up to a stop you could hear it still tapping.

I have changed the oil about every 2500 to 3000 mile for the last 8 years, I have ran Castol GTX oil all it's life the filler caps as 5 w 30 oil. one year I ran one quart of Castol syntech to a oil change and it (note seemed) to make the oil thinner and the oil pressure seemed to drop at a idle lower than I care for. so I switched it back to 5 w 30 untill the last oil change. since it going to be going on a long road trip in pretty warm weather, my thinking was to go with a heavier thicker oil to combat the heat and thermal break down of the oil

Well then, that rules that out on the face of it. Except Castrol isnt my oil of choice, it's more a 'feeling' than anything I can put my finger on.

Here's a couple questions:
When your car is warmed up, at what rpm does your oil pressure gauge reach its max?

Ever pull a valve cover.. any sludge in there? Dont mean 'milky'.. mean like greasy solids.

Too many folks talk about correct oil weight for their symptoms-keep in mind that taking care of the symptom is NOT taking care of the problem! If a problem really exists-there's way too many variables involved here!

How about explaining that. Those questions I asked were trying to find ALL the symptoms.. then you decide how and whether to treat the problem.

Nobody has mentioned that 134K miles is not an old engine. IMO anyway... I'm thinking maybe try a shorter Seafoam treatment (not the 20 mins the say) or the trans fluid treatment. I'm not sure on the previous owner but you've changed the oil religiously at proper intervals for 8 years, so I'm going with the engine hasn't been abused. But all that being said there's no telling for sure if the engine does have IMO a premature failure of a lifter or is it just sludge?!

Rocker arms are the last thing to get oil in an engine, lifters are next to last. Thick oil increases oil pressure but decreases volume. The thicker oil can't flow easily through main and rod bearings so it ends up starving the camshaft bearings, lifters & rockers. 5W20 is recommended and 10W30 is thicker, now you add Lucas on top of that. No wonder it makes noise ;)

Post #14 goes into a little more detail: https://blazerforum.com/forum/genera...-change-69643/

Well, my pressure max is at about 1200 rpm, warm. So I assume my bearings are in good shape.. If I get lifter tick, with my 10w30 plus Lucas then I'll be concerned.

I have never had lifter tick on any car I owned longer than three months since I started using Mobil1 or Valvoline.

And I am NOT real religious about oil changes

Same with me, I get around 42psi or so warmed up at speed, cold it's around 47 or so. It's hard to gauge it looking at KP & 550 being top, 275 at the middle... gauging all the little lines inbetween & what's what in PSI lol

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