View Full Version : Steam at Idle

07-09-2009, 10:48 AM
I have a 1976 90 Horse Chrysler that I just put on my boat. I thought I had all the bugs worked out but I noticed their is steam coming from the engine while I am idling. It is coming from the rear nostrils. It is enough steam that you can see it without having to look very hard. Is this normal or am I possibly having an over heating problem. Thanks

07-10-2009, 08:34 PM
"Sounds like an overheat - did you service the water pump? if not, time for a new impeller at minimum..."

07-11-2009, 12:44 AM
"Sean. Sprinkle some water on the cylinder head near the spark plugs. If it sizzles, you have a problem. Follow Grahams advice on the water pump and check the thermostat for correct operation.

In cold weather they would look like steam, but run normal. But no time for guess work, time to check."

07-11-2009, 02:39 PM
"It is also entirely possible it's simply some exhaust as well.

Those "nostrils" are exhaust relief holes - the water spitting from them, while a good indication that water is circulating, was not the reason they were put there.

Their primary function is to ensure that there is no excessive back pressure on the exhaust which would rob the engine of some of it's performance.

But best to be safe - assume there is a problem - rather than ignore it and weld your pistons into the block..."

07-13-2009, 04:29 PM
I have had the water impeller out and inspected it. It looked like it was ok. I am going to go ahead and replace it. I also sprinkled water on the cylinder head and it did not sizzle but it is hot to touch. Thanks for the info!