Can K&N xtreme top cause this...

[69HuggrrrPT]

A lean condition?

Reason being I have changed a few things recently(69 355) and now am overheating at highway speeds and idle. Before the changes the engine was only overheating at idle but fine while cruising, which is why I put a new Mark VIII fan with DC controller in.
I also changed the air cleaner lid to the K&N Xtreme top and was wondering if it's causing engine to run lean, therefore overheating at any speed? Has anyone had to fatten the jets with this lid?

Any guesses?
Thanks

[Fuelie Fan]

no pun intended, but that seems EXTREMELY unlikely. Luckily, it's very easy to check. put your old lid back on and see if it gets better. Does your engine FEEL any different?

At cruise, even though in-cylinder temps could be quite different if A/F changed from 13:1 to 14:1 (for example), heat rejection into the block I think would not be much different. Leaning the mixture also slows the burn rate, so I think you would see most of the extra heat go out the exhaust (higher EGT's) instead of into the block with ignition timing unchanged.

Beyond that, cruising is a very low-power situation, and airflow across the radiator should be very good. the cooling system should be more than able to absorb such a change, if it really did occur. I would focus on your cooling system if I were you.

[69HuggrrrPT]

LOL I knew someone would say something like that.
Yeah, I figured I would put the old top back on tomorrow, just to see what happens.

Anyway my cooling system was fine while cruising before the top and Mark VIII fan. I replaced the tstat with a 180* also, could I have trapped air somehow? How would I know?

[Fuelie Fan]

It could be any number of things I suppose. It could be something as silly as the fans spinning backwards if you wired them wrong! Did you make a shround for the fans? Are they thermostatically controlled? Did you put a small hole in the thermostat to let any air get through? Is the system building pressure?

[69HuggrrrPT]

I think I've found the problem. Yes the Mark VIII fan has a built in shroud and is pulling air correctly.
What I did was move the temp probe to a hotter part of the radiator so the fan would come on sooner and stay on longer. Seems to be working good now, will go to 195 and when fan kicks in goes to 185. I still don't know why at cruising speeds it was overheating when a fan isn't really needed. But oh well it is all good now. Oh yeah the Xtreme lid is still on.
Thanks for your help! :drive:

[Fuelie Fan]

Good to hear, have fun with it!