Mercruiser closed cooling system problems

Fresh water cooling is the best but you still have corrosion problems with the risers. Remove the manifolds if they appear clogged.

I was looking at new kits but I cant find one that has the same components as mine.

Mercruiser closed cooling system problems. One of the difficulties facing the marine cooling system or any cooling system for that matter is in separating the air from the coolant. Air is a very poor conductor of temperature and therefore will force a cooling system to overheat almost immediately if a significant amount is. Once the safety margin in the expansion tank is used up air will enter the closed system.

Since a mixture of air and coolant is insufficient as a heat carrier overheating will result. Some leaks may be difficult to find unless system is under pressure. Fresh water cooling is the best but you still have corrosion problems with the risers.

Mercruiser does not in my opinion have a well engineered exhaust system. Castings are too thin and prone to failure. My BBC was marinized by Volvo.

The swedish engineering is good but they are too proud of their spare parts. My first choice would be a Crusader. I have a 1989 Mercruiser 37 It seems to me that the closed cooling system is over flowing to the overflow tank but is not returning to the cooling system.

The overflow tank will keep filling up over the course of the season untill i pump it out. Never heard of an air lock in a cooling system. Im assuming it is not the raw water side.

Everything is so large and open. The water freely flows down to the pump. It is more likely you have a stuck closed thermostat or the coolant pump for some reason is not pumping.

Perhaps a loose impeller. Its possible that some debris is clogging the exchanger or oil coolersea strainer. If all that checks out check the exhaust elbows and manifolds for scale build up and restriction.

A stuck thermostat could also cause heating as could low coolant in the exchanger tank. Yup your understanding is correct. Also on OEM closed circuit Merc engines risers are always raw water cooled.

Which is another reason why a fresh water cooling system is worth having anyway. By rinsing the whole system before leaving the boat unused for some time you leave nothing but fresh water everywhere. A full closed cooling system cools both the engine block and the exhaust manifolds with the closed system.

The elbows are still cooled with raw water. Obviously a full system needs a bigger heat exchanger since the closed side of the system is cooling more of the engine. The temperature gauge at the helm will show the engine block temperature and nothing else.

Hi guys does anyone have an opinion on closed circuit cooling vs. Raw water for mercruiser engines. What are the pros and cons for both systems.

Is it worth getting a kit fitted to a 6 year old engine thats always been pulled out of the water. Even though the boat is out of the water on a trailer the block still has water remaining in it that doesnt drain out after flushing. Mercruiser closed cooling system problems.

Closed Cooling System MerCruiser engines may also be equipped with a closed cooling system. This cooling system is divided in two separate sub-systems. One uses seawater and the other uses coolant called fresh water.

The seawater system operation is similar to the standard cooling system previously described. If the overheat condition only exists when the boat is run at high speeds the cause may be clogged exhaust manifolds or risers. The Mercruiser has inspection ports on the font of the exhaust manifolds.

Remove the ports and visually inspect them for deposits that would restrict the water flow. Remove the manifolds if they appear clogged. Closed Loop Cooling Systems.

There are a number of different ways the cooling system can be setup closed loop half or closed loop full. Generally this means the salt-water gets sucked up and ran through a series of heat exchangers. On one side of the heat exchanger you have salt-water and on the other side you have coolant.

The coolant runs through the. 11-26-2009 1034 AM. I converted mine to closed cooling but I am in salt water.

Yes AF is slightly acidic and released scale and rust but since you are in fresh water you probably dont have much. Another benefit is that I could run a higher temp 160deg thermostat instead of the 143 and the engine will run more efficiently. You are looking at a Brand New freshwater cooling kit for Mercruiser applications years 1982-1998.

This kit will fit 43L 50L 57L and 62L marine applications. This is afull kit ie. This cools the engine block exhaust manifolds.

On average this kit will take 4-6 hours for installation. Mercury MerCruiser engines have either a seawater cooling system or a closed cooling system. Cooling while closed cooling systems are sometimes called fresh water cooling.

On engines with cooling system flow diagrams at end of section RPM. Mercruiser 350 MPI Overheating Problems As statedput the tstat inWithout itthe faster you run the enginethe faster the water passes through the systemThe faster it passes through the systemthe less it cools the engineWhen you slow the water inside the engine you give sufficient time for the heat to be displacedtransferred into the waterCharlie. 2004 Mercruiser 496 Mag with closed cooling system.

I went to drain my cooling system. The hand pump was missing so I applied 50 psi pressure to the cooling system drain valves. I then neglected to pu.

My pre departure checks in the engine room showed me that the port engine closed cooling system required a coolant top up. This is a common occurrence on the. What has me stumped at the moment is the cooling system.

The PO stated that the port engine started overheating and started losing coolant. There was a leak on the port side of the engine from the manifold. I was looking at new kits but I cant find one that has the same components as mine.

I may have a closed cooling system but not sure. So what to do. Flush the raw-water side of your cooling system each year as a part of your winter layup procedure.

A couple of products Ive used are Seaflush and Forté cooling system flush. Before you flush be sure to remove the sacrificial anodes screwed into your heat exchanger and replace the anodes with new ones after the flushing. All of the 470 and 37L versions used closed cooling systems.

The aluminum circulation pump impellar was located on the front end of the camshaft. This required a way to separate the cooling system from the engines crankcase area. The cam passes through two seals which are press fit into the timing chain cover.

The MerCruiser engine is getting insufficient oil supply to moving mechanical parts. Check the motor oil level and fill if needed. Make sure the engine oil is flowing through the oil passages clean passages if necessary.

Engine Overheating Cooling System. Loose of faulty serpentine drive belt. Replace the serpentine belt with a new belt.