New to me Colbalt, Overheating only while pulling tube or ski

[zaayer]

I have a new to me 2012 Cobalt 276 with a 8.1Gi-CE-Q catalyzed raw water cooled engine. It overheated (limp mode) when had my survey but bought it anyway with the advice from the surveyer. I pulled off one manifold and took it to my local shop and they said it looked good. I found that the exaust manifold thermostats were not functioning correctly. I replaced both of those and the engine ran cool from idle to full throttle. However i later found that the engine overheated when plowing through the water making waves or pulling tubers / skiers. I changed both the engine thermostat and the impeller. The engine temperature came down a bit but I will get a overheat warning (no limp mode) sometimes when pulling a tuber and only while pulling. When the overheat happens the engine temperature shows around 180-190 before the warning comes on. If if drive more sensible (straight) the warning buzzer turns off. I also used a infrared gun and the port side manifold is hotter (185-195) than the starbord.
Does anyone have any advice on where to start looking for a problem? I checked the hoses and i can't find where there would be any sucking of air.
Below is a list of codes my surveyer pulled when I first bought the boat. I don't know if any of these sill exist.

Thank you so much for your help!
Brian

Previously Active Trouble Code List: 7



1. SPN: 442 Exhaust Manifold Water Temp 2 (EMWT #2) Fault

FMI: 3 EMWT 2 Voltage High



2. SPN: 697 ECT Gauge Driver Fault

FMI: 5 Temp Gauge Driver Voltage Low



3. SPN: 698 Oil Pressure Gauge Driver Fault

FMI: 5 Oil Pressure Gauge Driver Voltage Low



4. SPN: 699 Trim Gauge Driver Fault

FMI: 5 Trim Gauge Driver Voltage Low



5. SPN: 924 Check Engine Lamp Driver(ETC) / Water In Bellows Driver Open or Short to Ground(IAC)

FMI: 5 Voltage Low



6. SPN: 1213 MIL Driver Fault

FMI: 5 MIL Driver Open



7. SPN: 1386 Exhaust Riser Water Temperature 2 Fault

FMI: 3 ERWT 2 Voltage High

 

[alldodge]

Lets start with the motor serial number

 

[zaayer]

Thanks for the reply Alldodge. The serial number is A201349

 

[alldodge]

Thanks
Our expert on VP is @muc and before I call him in I wanted to get the SN because that would be the first thing he would ask for.

The 5V reference voltage is low. The 5V Ref can go low by almost any of the sensors on the motor. If one starts drawing more current it pulls the voltage lower. When it goes low then many of the other sensors start sending errors to the PCM

Use a voltmeter and measure the voltages on a sensor or 2. Each 5V sensor will have at least 3 connection, 5V, Ground and Signal

 

[zaayer]

Those error codes were from April when I purshased the boat. The batteries were shot and I have since put new batteries in. I am not sure if that would have caused some of those codes. I am getting ready to take it to Kentucky lake for 12 days with my family and I am hoping we will not run into any further problems. I sure would like to teach my boys to ski on this trip so I am hoping to get this fixed.

 

[alldodge]

I'm just wondering if its a actual overheat or a sensor issue. The largest issue is there is hardly any of us that know the new CAT type motors, and VP is the worst because of close hold on information MUC is one of those that does and most all of them need to use a scanner to find out what is really going on.

I'm in the process of going thru the parts inventory of your motor trying to understand how the cooling system works. Merc used things like poppet valves which were a problem. So looking trying to see how it interacts

 

[alldodge]

I'm seeing your boat has a separate thermostat for each exhaust. Could be the issue why one is hotter then the other.

You closed cool (heat exchanger) or open cool?

 

[zaayer]

The boat is open cooled. I changed out both exhaust thermostats a few months ago. The old ones were pretty beat up. They were causing the limp mode overheating when i first purchased the boat. The boat couldn't run for more that a few minutes at above idol with those. Now i only have problems when under load (tubers). I guess one of the new ones can be faulty!
Here is more information that may or may not shed light. The boat was located on the Chesapeak bay. It only had a 100 hours when I bought it. I was worried about rusted manifolds and elbows. I took off the starbord manifold and it was in good shape. I never took off the port side manifold. I figured they should be in the same shape since they are on the same engine.

 

[alldodge]

Being in salt water at one time and open cool could put scale over things and restrict water flow. After the raw water pump it feeds thru the oil cooler. Remove the hose going in and look inside to see if there is any build uup

Have you looked at the motor thermostat?

 

[zaayer]

First of all let me say "Thank You for your help"! You are very generous to be spending this time to try and help me. Now on to the engine.
I have replaced the motor thermostat as well. After replacing it the engine ran a little cooler. It did not overheat as easy when pulling. I also took off the hose before the oil cooler. The oil cooler had absolutly no build up. It was perfectly clean.
What I don't understand is the engine temperature is getting hot. With that, the port manifold seems hotter than the starboard as well. I am getting the port and starbord temperatures from a infrared thermometer. Do you happen to know what temperatures are considered hot for those manifolds? Perhaps the manifold temperatures are not the problem. I am tempted to get something that can read the engine codes. I just don't want to spend the $600 for one of those.

 

[tpenfield]

You will probably spend at least $600 in irrelevant parts or mechanic's timeinstead of buying the code scanner. The new CAT engines have lots of sensors and they all seem to play games.

I'm currently going through that with my Mercruiser. Just spent $450 upgrading my computer diagnostic software to the latest connectors, software, cable, etc.

I would recommend getting the scanner, at least, if not the whole computer diagnostics. . . maybe you can flush the cooling system with barnacle buster, since it has been in the salt.

 

[alldodge]

One side being a bit hotter then the other is normal. Have always seen a few degrees different because the water flows the path of least resistance

Maybe a clue, in pic above the thermostat kit item 9 is listed as 3831426, and fresh water cooling

In other listing as 3856961 and "160 degrees" which would be for a raw water cooled motor

Only closed cooled motors get a 180* thermostat

 

[zaayer]

It looks like the Rinda Techmate pro scanner will work. https://www.rinda.com/rindashop/shop/techmate-pro/techmate-pro-94070m
Do you recommend it or the PC diagnostic kit
https://www.rinda.com/rindashop/shop/diacom/diacom-94030c-kit

 

[zaayer]

I just realized that I put the 140 degree thermostat in the engine. I should have gotten the 160. That explains why the boat runs a little cooler.

 

[alldodge]

The exhaust thermostats for both raw and closed use the same thermostats, so were good there. How does the excess water flow the the exhaust elbows and out?

 

[zaayer]

The exhaust thermostats for both raw and closed use the same thermostats, so were good there. How does the excess water flow the the exhaust elbows and out?

Sorry alldodge, I'm not sure what you are asking.

 

[alldodge]

Sorry alldodge, I'm not sure what you are asking.

This is what I mean by not enough info, and not being able to see a complete cooling system routing.

The motor should have the 160 Stat, but even with the 140* your motor is getting to 180-190 (unless I missed something again). The water pump should be supplying more water thru then the motor needs. All the extra water should go straight out the elbows that doesn't go toward the manifolds or block.

 

[zaayer]

This is what I mean by not enough info, and not being able to see a complete cooling system routing.

The motor should have the 160 Stat, but even with the 140* your motor is getting to 180-190 (unless I missed something again). The water pump should be supplying more water thru then the motor needs. All the extra water should go straight out the elbows that doesn't go toward the manifolds or block.

Looking at the engine, I don't see anywhere that excess water gets out. The only water line connected to the elbow comes from the exhaust thermostats.

 

[alldodge]

This is where we need @muc but just my thoughts. I don't get the exhaust thermostats on the exhaust elbows, but they must be used to somehow keep the Manifolds at correct temp.

Water comes in and thru the top of the thermostat housing then out toward the bottom of the manifolds. Water comes up thru the Mans and out the elbows. There is a Tee feeding each Man going to the Ex Stats. They are called Stats so I assume they open when needed. Don't know when the need is triggered. On Merc's the raw water is always going out the elbows and only exchanges the Mans when temp reaches a preset point

So how ever VP is doing it is not clear to me. Maybe its called a Ex Stat when its actually a check valve. It maintains a set pressure inside the full exhaust system. Right now don't know

 

[alldodge]

Thought of something else. The VP outdrive has a fitting on the top where the intake hose connects. If it gets corroded or slightly clogged, the water is reduced