Temperature 454 PMC

PCM, your engine falls into the normal operating temperatures that the engine needs to run economically, it will be in the thermostat housing on top of the intake

Yeah, where is that outdrive thingy? I can't seem to find mine!

Thanks on the temperature question, so it seems that the 170 - 190 degrees is actually not a problem then? I actually have an old Chevy truck that has this same engine and it runs to the hot side also with no problem. Maybe just a quirk of the engine.

OK on the needing the thermostat, and I have never seen the guage go over 190, never fluctuates rapidly. Maybe I just need to replace with a 143 just as routine maint. These things are relatively inexpensive and supposedly easy to change out.

My 454 runs right around 160. It will climb to 190 after returning to idle after a speed run of considerable length. When it does this it only takes about 30 seconds for the temp to come back down to 160.

Think that you can get a 143 for this engine, but in any case I took the boat out for a long run today and even running hard for about 10 minutes it never got over 180 and just cruising it stayed at 160 - 170 so I think that all is OK.

Yeah, this is one big boat as you likely know and the gas tank ( all 40 gallons of it! ) has to be removed to get at the rear muffler clamps. HEAVY!!!! So I have postponed the muffler removal until the fall. I actually just got the boat back in the water Saturday as I had to put a new lift in my boat house that would lift 4,000 pounds ( as I said, HEAVY ), this thing is no Tique! I have taken it for a couple of good runs and am in process of "learning" the boat. Am past the temperature issue that I thought that I had, but will still use some of the advice just to keep everything cool. I discovered that the "fuse system" is like the one on my Harley, too much load and EVERYTHING shuts down, the boat just plain stops! When the fuse cools off all is good. Apparently you can't run everything at once, ie bilge pump, blower, ACC, etc. Or maybe this is yet another forum! The 454 is awesome though and will take that big boat for a big ride quickly. Later this week I will try to take some pics for the dairy. Thanks for the curiousity.

Sandy, how did the 145 work out for you. I'm thinking about changing mine out as well.
Steve

My 454 runs at 160 and after running 38 - 43 MPH pulling a skier then back to idle it will spike up to 180.

I have another issue! When I turn on the navigation lights the temp gage goes up 20 degrees and the alarm will chirp. I have seen some pics where folks re-wire the daisy chain harness to a block design. Could this be the problem? Some of the same weird issues when the blower is running.

tbeard wrote: I have another issue! When I turn on the navigation lights the temp gage goes up 20 degrees and the alarm will chirp. I have seen some pics where folks re-wire the daisy chain harness to a block design. Could this be the problem? Some of the same weird issues when the blower is running.

Yeah, this is basically caused by marginal wiring. I got a bus bar, and ran a new ground from my engine (you could do it from your battery too).

I connected the new ground to the bar, and tied back to the bar from multiple points along the daisy chain. It definitely stopped my temp gauge from moving when accessories are turned on.

A general clean up and replace of terminal ends, and suspect runs of wire help as well.

I just had a PCM 454 thermostat convesation with them last week, which is why I asked. 143 sounds like the much more common 351 thermostat.

You said 145 in some spots and 143 in others. I think I get it now, you meant 145 the whole time.

They are completely different units and will not interchange between the 351 and 454, so yeah kind of a difference.

You can't put a PCM 143 thermostat (for the 351) in a 454. I don't want someone to get confused and try that. The 145 is significantly more expensive unfortunately.

I just had the the t-stat out of the BFN last week. My BFN is running a 143 degree t-stat that looks nothing like the one for 351 pcm. The t-stat in the BFN has a chrome cup and a long plunger the whole t-stat end to end is roughly 3 inches. The t-stat that ski-dim sent me is not the same as the one that is currently in the boat.

Yikes, thin skin alert