New closed cooling - steam!?

[Grant Brown]

I just installed a San Juan enginering closed cooling system on my 5 L V8 2007 model. It is an alpha one G2 drive. The engine stays cool at about 165?F but the water coming out of the exhaust is hot to the touch and is steaming. Outside air temperature is about 55?F. Is this normal? When I used to have the raw water system hooked up to the hose there was never any steam. The system was full of water and the muffs were on the drive with water on. I ran it for about 10 minutes.

 

[Scott Danforth]

Something is not right. Have you run it in the water? New impeller or old impeller?

 

[thumpar]

How many hours on the engine before the closed cooling was installed?

 

[Grant Brown]

Have not run it in the water yet.
The impeller is a question mark. I have only had the boat since July and have not replaced it yet.
The boat has "low hours" or so the previous owner said. He did not do much in the way of maintenance though so who knows for sure. The water jackets that I saw today did not look too bad compared to other salt water motors I've seen.
The weird thing is that the engine is not heating up beyond the 165? mark and takes awhile to get there. Before I installed the cooling kit, the temp would stay at 180? on muffs or in the water. The new thermostat is a 160? unit.
Thanks for the fast replies.
Grant

 

[tpenfield]

Is it the 'full' closed cooling SJE system or the 'half' system?

I installed the full systems on my twin mercruisers no steam out of the water discharge at the out drive/prop. I suspect that you are not getting enough water flow through the heat exchanger so the water is getting quite hot. See if you can get better flow while on the muffs, etc.

The concern would be if the engine will overheat, once under load.

 

[Grant Brown]

It is a full system. I am going to replace the impeller this week. It hasn't been done yet anyway.

 

[thumpar]

If the engine was run in salt with a raw water system you could have problems with the exchanger clogging up.It is not recommended to change after a certain amount of time.

 

[Scott Danforth]

The alpha raw water pump does not have enough volume and pressure for the restriction of a full system HX. There is a reason Mercruiser never offered a full system with an alpha drive

 

[Grant Brown]

I spoke to the top guy at SJE this morning. Nice guy, very helpful, and while he didn't actually say the Alpha was not efficient enough to handle a full closed cooling system, it was probably implied by the fact that they always recommend a new raw water impeller when doing the install.
I got the kit today and be damned if I could get the lower separated from the upper. I think the shaft might be stuck. I posted it in a new thread:
http://forums.iboats.com/forum/engi...2-alpha-1-gen-2-lower-unit-shaft-stuck-in-leg

 

[thumpar]

You could install an engine driven pump if you think it is low water flow.

 

[tpenfield]

Grant - I just sent you a PM.

It will be interesting to see if the impeller improves the situation. The Bravo drives have the sea water pump on the engine, and that may be necessary to get enough flow through the full system. Lots of heat to get rid of . . .

 

[Fun Times]

The weird thing is that the engine is not heating up beyond the 165? mark and takes awhile to get there. Before I installed the cooling kit, the temp would stay at 180? on muffs or in the water. The new thermostat is a 160? unit.

Technically speaking, 180 degrees is/was to hot to begin with on a stock system even though it could just be an in-accurate gauge, temp sending unit or both as a combo. Hopefully it's just a weak/aged impeller.

Typically on the stock system, the gauge reading might go right up to the 175* range.. 179* is the very high end. Anything more than that on a "normal running" engine with a 160 degree T/stat is usually a very in-accurate gauge, sending unit, wiring, 12 volt power/ground problem or all of the above.

When you install a new impeller, It may be a good idea for you to coat the gear housing base gasket with Mercruiser/Quicksilver Perfect Seal or a equivalent Permatex Aviation Form-A-Gasket that's found in most auto stores to help with any unseen overheating issues you may have as seen in the following link. Alpha One Generation II Over Heat

Bt Doctur may have a good suggestion to watch out for with the impeller pulled apart as well.

You will need to get yourself an infrared heat temperature gun in order to know what all the temps really are. http://www.harborfreight.com/catalog...rared+temp+gun

If you continue to truly have high temps after checking/repairing all the normal things that could go wrong with the cooling system, then you may have to install an engine mounted impeller kit with a through hull water pick up while still utilizing the alpha impeller to help keep the stern drive cool.

Did you bleed out the air pockets within the new closed cooling system....Antifreeze side? if there's air in the A/F side then the engine could run hot while tricking the sensor to read cool with only air (no liquid) around the sensor.

Good luck.