verado 150 running hot

[dieseldan2001]

Hello, I am new here. I have a 2006 verado 150 with about 488 hrs on it. We live up in MN so the boat never sees salt water. I took it out for the first time this year a few weeks ago and I unfortunately plugged my cooling passages almost immediately from trying to back away from shore as the dock wasn't put out at this particular launch. Now i got out into the lake and once i started to plain off, my temp gauge went up to around 175 and would drop back down and heat back up. This was at around 4500rpm. Any faster and the temp would climb higher, so i never let it get over 183 once. Fast forward. I brought it into the dealer knowing something was plugged. First they tried a water pump, not knowing if it had ever been replaced. No change next time i went out. Still running hot at higher rpms. So now they have done a t-stat, pulled and cleaned poppet valves, and cleaned all other screens. Tons of rocks/sand was found inside. They ran it on their dyno and it still runs too warm. They hooked up a clear line and found air bubbles in the water stream. They are now thinking its a head gasket/head issue. I am beside myself as the ecm never has shown an overheat code in its life. Not sure how that could happen! Oh they also said it seems like there is exhaust gas in the cooling stream as the new t-stat has a black hugh to it already. Anyone else have any ideas on other things to look at? Could something in the mid section or lower unit have cracked? Any help would be so appreciated.

 

[henleyhale]

.. well inspect the head gaskets, gaskets are cheap, you can run it up to warm on muffs and use an infrared to see which side is getting hot then pull that one off and take a gander. Post us some pics of the head gasket, we arent talking about a ton of work for that, heads are 8 bolts i think. If it was a failure in the lower unit water would be pouring out of the crack above the lower unit. Also if you clog up one side real bad the other side can still cool and cause mixed temp readings so you can overheat one side and not the other in a i just ran my motor through the silt situation. Also sounds like you can plug up just one passage in the jacket completely allowing water to frow away from but not up to a particular cylinder.

 

[schematic]

.. well inspect the head gaskets, gaskets are cheap, you can run it up to warm on muffs and use an infrared to see which side is getting hot then pull that one off and take a gander.

only one head (inline engine)

 

[dieseldan2001]

Yeah this is an inline 4. it is still at the shop, if they pull the head I will try and take some pics of it.

 

[dieseldan2001]

I just got a second opinion on this from another marine tech. He asked if when the original shop did the water pump if they did a kit or just the impeller. I looked at my receipt and sure enough they only did the impeller. He thinks that with all the debris that i sucked up (including small stones) that the housing is scored or that the o ring that seals the water pickup was nicked when they installed it. He said the heads on the verado's are so strong that it is rare to see anything like that ever happen unless there is a severe overheat. Anyone else have an opinion on the impeller housing?