So how much blowby is too much

Update: ordered a new PCV should be here this weekend or early next week. Will update this thread with results.

 

I’m interested in seeing how this works out. I have a high mileage 2.7 with a decent amount of blow by. More than I’ve seen on other engines. If this works for you I’ll be replacing my pcv to see if it helps. I pulled it out and it seems to be working okay

 

IMO if you have legit blowby like OP is claiming a PCV may help a little but not much. Your rings are toast and it's only a matter of time where you'll burn too much oil and have to rebuild the engine. Though, you're probably fine for a long while most likely.

 

Thanks for the info. I just put this engine in miles unknown. Currently have a little over 2k miles on it since the swap and it hasn’t used any noticeable amount of oil. The last one had even worse blow by and was about to spin a bearing. Still need to check the PCV out though

 

So I just replaced the PCV valve, it took all of 1 minute. There’s still a good bit of airflow coming from the fill cap, but when I rest the cap on the hole it suctions in place and doesn’t blow off or anything. Which leads be to believe the new PCV is working fine. The old PCV seemed to be malfunctioning. I blew through both ends and got air flow through both, though from valve cover to intake I got more air flow.

so long story short $10 part, not sure if it really fixed my problem. But I believe my problem is not a “problem”

 

How much oil is used between changes ? Is it enough that I has to be added between changes ?

My 3rd gen 4Runner w/3.4 had 258k, burned no oil between 5k services

my current 2nd gen DCSB has 306k uses no oil between 5k services

BOTH had/have some appreciable pressure at the oil fill when running.

if it’s not using oil, I doubt it’s anything to worry about.

 

Could just have bad valve stem seals.

 

Yeah I use no oil between changes, so it’s technically not “blowby”

 

I doubt it would keep the engine from running for a very long time. As long as it does not run low on oil it should be fine. (Yes I know it shouldnt be burning oil but if you are planning on running the motor till it dies.) Blown HG is another story... If you leave one of those long enough, the cold spot on the cylinder wall will stay in and you will no longer have circular cylinder walls lol.

Personally I'd drive it till it gave up on me. And I would know my truck gave me it's all.