740 gl knocks on start stop when get warm or press on gas. There is oil in air cleaner intake pipe. no gasket leaks on intake manifold or valve cover gasket. what is the problem? Also my brake goes on then off?

 

How long has it done this? Did you recently change anything? Does the knocking start (or become more previlent) when you accelerate and/or decelerate? How many miles does the vehicle have?

 

winter time. Changed pcv oil trap. knocking on startup then stops as warms up and when driven
No engine light

 

First, I am not a mechanic, nor do I play one on TV. However, I found an article that may help you:

https://www.brakeandfrontend.com/vol...ged-oil-traps/

You may have a sludge/oil blockage in the lines when the engine is cold, and the oil is thick. Once things warm up and the oil's viscosity goes down, then everything is OK. Just my thoughts and observations.

David

 

What additive can be used to clean the sludge /oil in the engine and lines? What grade of oil to be used in oil changes to help mininize this? 10w30 or 10w40

 

I've found that STP makes an Engine Flush that may help. Make sure you follow any instructions on the bottle. As far as engine oil, take a look at your owners manual and it should tell you what to use. There are differences between turbo models and non-turbo models, so the manual will certainly help.

I also found another website that can explain things much better than I.

https://www.carparts.com/blog/how-to...engine-sludge/

There are other high mileage motor oils that I would recommend. I did put on 493K on an American van using Castrol Syntec synthetic oil for high mileage vehicles. It worked well for me. Again, I am not a mechanic, just someone that is trying to help.