Griff,

Yes. From the dash gauge. But I'm more concerned with the change I'm seeing, rather than the actual temp. 180° is not terribly hot, but it seems to be slowly creeping higher and higher as time goes by. I wouldn't disagree with the probability of a discrepancy in actual temp and gauge reading, even though it seems to be reasonably accurate. My main concern is that the boat USED to run ~160-165° as long or as hard as we ran it. At first, I just noticed that the temp would spike a bit after a hard run, which is what led me to install the oil temp gauge. But now it seems to climb up to 180° and hover there, so far to date, even if we are just mildly cruising. My concern is that it will eventually get to the point it is running over 200°, then over 220°, or may suddenly just run up and alarm out and shut down when we're at a highly inconvenient towed distance. My wife says I'm paranoid or looking for something to tinker with, but, truthfully, I just like to stay ahead of things that can ruin a weekend and/or checkbook.

Where would one take a more accurate reading?

The engine was built in 2001. I have no idea if it is VV compatible. The transom assembly says "SmartCraft" on it. Not sure if this is indicative or not. What would I look for to determine VV compatibility? Call Merc?

Thanks. Brad.

UnderPSI,

OK. Reread it. Care to be more specific? What to do? What to look for?

Thanks. Brad.

You can smoke a housing and impeller in 1 trip. Suck up some sand and groove the housing. I just put a new housing on my STRBD engine and it is significantly higher pressure. From 5psi before to 15psi now at idle.

Rookie,

I wouldn’t doubt that. Pretty sure we did just that a number of years ago in our Rinker at the party cove on Brookville lake. Never been back, and we don’t get anywhere near sand or gravel or anything such on either of the lakes we frequent now. I’m sure they will have a look at it when it’s apart.

Thanks. Brad.

BC - have you considered it may be global warming ?

SB,

That you, Mr. Gore?

Thanks. Brad.

I have friend who has a late 2001 build 496HO and he has VV mobile attached to his engine. Here is a link with a "contact us with your serial number to verify" VesselView Mobile (mercruiserparts.com)
I would use a laser temp gun on the Tstat Housing to check temp. That is where my temp sender is as well. Not sure if the 496 is the same though.
Have you ever changed the coolant??? Possibly getting weak and not cooling as effeciently??
Just throwing some ideas out there, but the first thing I'd do is verify the actual temp vs what the gauge says. I had to replace both of water temp gauges because they would act up and read high and act wierd intermittently..........and my gauges are the same as yours.

Griff,

Thanks for the link. We are heading down today and I will check when I get to the boat. Any idea where the engine serial number is located? I have been able to track it down through Merc from the transom ass’y serial number, but won’t have access to those notes until Monday morning. I suppose I could call Merc again….

I will acquire an IR thermometer and verify agreement between gauge and actual temp, IF I can get to it (intercooler may be in the way).

I have not done a full drain and replace, but the coolant reservoir was completely dumped in late ‘22 when I cracked the reservoir during the fuel injector ordeal. I could also tell some was lost when it was in the shop last, when they swapped the T-stat for a restrictor plate.

Thanks. Brad.

Your engine serial number on a 496 is usually on a sticker on the heat exchanger, starboard side of it. If not there it will be on a metal tag down near where the starter bolts on to the block.

Your temp senders are located on the crossover tube (where the heat exchanger mounts to). The sensor on the top of the crossover on the port side is for your dash gauge. There is another sensor on the starboard side of the crossover that is for the engine computer.

Are there any rubber hoses that could begin to collapse when softer as in temperatures go up? The wax pellets inside of the T-stat can slowly degrade. I am not familar with all the specifics of your cooling system but if your system is up to the task than you have a component that is beginning to fail. Revisit all of the basics and you will likely find your problem. Pick through each piece of the system, understand it and inspect or replace.