Cooling system Nissan 3.5

[KAGY]

I have a couple of Nissan 3.5A engines that have same problem. Low cooling flow. The engine has to be at moderaltely high speed (at least half) to get much flow. At low speed I get steam. I have replaced impellors but not much help. It seems that the upper to lower unit attachment process has the tubes sliding together with with no seal. Is there a gasket or tube that is supposed to be there? Any ideas??

 

[TOHATSU GURU]

Re: Cooling system Nissan 3.5

Block problem, headgasket, basegasket, or the cup where the impeller rides is worn out.

 

[jeds2000]

Re: Cooling system Nissan 3.5

I have the same issue with my 3.5A. Just steam until you give it some throttle. I pulled the lower unit but could not find an impeller. It also seems to run a little hotter than the normel outboard at all speeds. Did you ever find out anything about how to resolve your problem?

 

[TOHATSU GURU]

Re: Cooling system Nissan 3.5

The impeller on the 3.5A is on the propshaft, not at the top of the lower unit.

 

[KAGY]

Re: Cooling system Nissan 3.5

I have not found the solution yet, I have not broken the whole engine down to look for blockage in the block although I have done that in the past and it did not help. The next time I try to break it down I think I will try to seal the tubing from the impellor to the block better ( if i can find a way)