I've used Seafoam in the past though I now use a different product to decarbon an engine and have never known either of them to cause leaks. As suggested above, however, I'd change the oil soon after the treatment.

Well, while not an L series, I am getting ready to be in a similar situation with another Z, This weekend I will be starting up the JMD engine I put in my Z32, By the paperwork attached to the engine it has been 2 years since it was run and has around 26K on the clock. It was compression checked right before it came to me, but not run.

I drained the gas for the tank-the car had not run in over 2 years either and this was the stinkiest gas I have ever smelled. I am going to pump some carb cleaner through the tank and fuel system-but not to the injectors because everything I could find says using conventional dedicated injector cleaning solution the injectors on a VG always results in corrosion in them followed by expensive replacement.

I have both Seafoam and Marvel Mystery oil, and intend to use one in the gas and the other in oil-along with Rotella-for the first 500 miles(monitoring the oil and modifying this schedule as led by the oil consistancy).

This engine has around 26K(documented) on it, but because of sitting up I want to give it every opportunity at a long and healthy life. as I plan to keep this car as a companion for my 240Z

Any thought or suggestions?

Will

PS this was the cleanest used engine I have ever seen, (not the typical pressure washing patterns under the protective coating) and it was very obvious the PO loved the car it came from-the best spark plugs that can be found for this engine were in it as was a Greddy OIL sensor adaptor, and the any other longevity touting JDM tidbit(most of those that will fit will end up on my 240Z).

Edited December 11, 200816 yr by hls30.com