- Joined
- Sep 28, 2002
- Messages
- 39,793
Although I think a 20w-50 is overkill, this is one case where heavier is better. There are few exceptions in the used oil analysis section where a 30 weight out performed a 40 weight. Most are of the relatively short OCI and perhaps under extreme climate. In this engine ..lighter weight oil yields virtually no benefit since engergy conservation is mostly a waste of time. Check the owners manual. The use of 5w30 is strictly NOT recommended in above freezing conditions and 10w30 has a (preferred) notation after it (connect the dots). This engine spec'd higher weight oils in more relaxed energy environments in previous years ...especially in the 4.2 and 4.0 (same bearing and oil system design- only the 4.0 adopted the 2.5's better flowing head design).
I would do the Auto-Rx treaments with any old oil (read the over 100k instructions twice ...clean-rinse-clean-rinse) and maybe consider pulling the valve cover to see what it looks like. Don't physically remove anything unless you're commited to getting it all out (very difficult to do)..and keep in mind, if you find a sludge cache, that there is a limit to the amount of physical material that A-Rx can suspend ..and a few filters can contain.
A 15w40 should be easy to use in your climate ..or virtually anywhere that stays above zero for most of the winter. I would be reluctant to use a 30 weight under anything but extreme climate conditions. I would use a synthetic xw-40 before going to a 30 weight (HDEO or not). I would only use a 30 weight if all other oils failed to manage the problem.
By all means dump a couple of cans of Seafoam into the tank and consider trying FP. Something many members here have had decent success with.
Good luck!
I would do the Auto-Rx treaments with any old oil (read the over 100k instructions twice ...clean-rinse-clean-rinse) and maybe consider pulling the valve cover to see what it looks like. Don't physically remove anything unless you're commited to getting it all out (very difficult to do)..and keep in mind, if you find a sludge cache, that there is a limit to the amount of physical material that A-Rx can suspend ..and a few filters can contain.
A 15w40 should be easy to use in your climate ..or virtually anywhere that stays above zero for most of the winter. I would be reluctant to use a 30 weight under anything but extreme climate conditions. I would use a synthetic xw-40 before going to a 30 weight (HDEO or not). I would only use a 30 weight if all other oils failed to manage the problem.
By all means dump a couple of cans of Seafoam into the tank and consider trying FP. Something many members here have had decent success with.
Good luck!
