What temperature?

[Surcouf]

one question for you guys: I usually run my engine "lightly". I was "trained" by my father, who was defining acceptable rpm for multiple hours cruising as pretty low, and I may be running now my engine unnecessarily low...

When I run my engine "my way" for a couple hours hours on a day without wind, pushing the C27 at 4.5 knots, I barely get 130F. I was assuming that I had an issue with my thermostat, or that I had installed it wrongly (dissassembled, re-assembled, no change)

Yesterday, I ran the engine "a little harder" for one hour, facing winds of 20-25 knots, seas a little chopped but nothing crazy bad, still going 4 to 5 knots; and temperature came to stabilize at 150-160F.

Does that mean that the thermostat is actually working fine, but only when I runs the engine harder? Or should I have 160F even at low rpm after a certain period?

Thank you

[edwardc]

Since the water up your way in RI is pretty cold (compared to the Chesapeake), this sounds about right to me.

My FWC A4 runs at 180 when under any throttle, but cools down to at least 155 at idle in neutral, even in the middle of the summer when our water is quite warm. Goes even lower in the early spring when the water is still cold.

[Ando]

Do you all think it would be safe to close the bypass and run it cool for the season and track down the blockage in the winter? Is there an issue with closing the bypass in other words?

[edwardc]

If you still have a thermostat installed, you should not close the bypass all-the-way. With the bypass closed, and the thermostat closed (as it would be when starting cold), there will be no water flow at all until the engine warms up. This can quickly overheat and damage the lining of the exhaust hose, and even melt a plastic waterlift muffler if you have one.

It's the reason the bypass exists in the first place.

It doesn't take much, but you must have some water flowing through the exhaust system to prevent damage. Years ago, Hanley did some experiments on reducing the exhaust waterflow, but I don't have the link handy.

[Ando]

Ok guys, RWC late model with overheating which I plan on tackling this weekend. A bit of background, I recently did a muriatic flush of the cooling system. Today, to prepare for this weekend's task of resolving the overheating (and hopefully to get a better idea where there might be a block in the cooling system) I got a laser heat gun and at about the 15 min mark pointed it at different points of the engine and these are the readings that I got.

Thermostat gauge went from 140 to 160;

Spark plugs were in the range of 180-185 (#4 being the hottest);

A bunch of points all over the head were around 160-174

Manifold was mostly cool (like 150 or less) so was the area around the thermostat housing and the water jacket plate was even cooler.

The connection from the manifold to the exhaust was very high (like 340)!

Does this point to the area of the blockage in the cooling system being at the manifold exhaust connection? Is that where I should start looking for the blockage? I read somewhere that that particular connection is a common problem area. All input appreciated. Thx in advance

[joe_db]

I am not sure why this popped up now, is this still an issue?
Some spots on the manifold are not water jacketed and get quite hot - FYI.

[Marian Claire]

Joe. I am not sure of this but I think each time a vote is cast the thread gets "bumped". So they pop up without a new post.

Dan
S/V Marian Claire

[W2ET]

Hi, Dan. That's correct.

Bill