Exhaust Temp 1301F

[BigWillyv]

Hi All!

First post here (new member), been reading topics for awhile and finally pulled the trigger on my first Cobalt! Boat's a '19 R5, with the VP380; 381 freshwater hours. It took about 2 years to finally find the right boat. Hoping someone will be able to help me, after reading through a bunch of previous posts I haven't found an answer. During the survey it was noted that "O2 sensor 1 and O2 sensor 2" had high temperature readings (~1400F) during the sea trial. I had it running on the hose at home this weekend and was able to see on the volvo engine computer that the "exhaust gas temp" was displaying ~1300. Surveyor used a thermal imager at sea trial and did not see any hotspots to confirm this temp. I used my IR temp gun and went over the manifolds while i had it hooked to the hose- same result. Both manifolds were around ~165F at various places. Here's the interesting part (to me)- No fault codes, no trouble codes, no performance issues whatsoever. Boat ran all the way up to ~5800RPM without a hitch multiple times. Does this seem logical/normal?

I'm thinking I have a bad O2 sensor or two possibly? Any idea why it wouldn't be setting any check engine or trouble codes? Last thing I want to do is melt the motor down from running it too lean or cause some other damage. I just finished up some routine maintenance (plugs, oil, impeller etc.) and want to make sure she's ready to go before I take the family out! Appreciate the knowledge and help!

Thanks!

[AsLan7]

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So glad you found us BWv....

Your O2 sensors monitor the catalytic converter temp which can range anywhere from 1200-1600 degrees (sometimes even higher!) to effectively burn-off harmful emissions. Your manifold temps are MUCH lower (normally around 160). Your boat is operating properly, and like you mentioned, would be throwing codes if things were amiss.

Any pics of your rig?

And welcome aboard mate!

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[BigWillyv]

Thanks Aslan- appreciate the response. I was thinking that normal O2 sensor temps usually max out around 650F, so i was surprised to see that high of a reading. I'm used to seeing 1200-1400 on my diesel truck when pulling (pyro is mounted right in the collector pre-turbo)- just wasn't expecting to see it on the engine readout..... No warning lights or alarms so off we go!


Here's a pic of the lawn ornament in all her glory!

Thanks again!

[stifflkd]

Ignore the Exhaust Temp 1301 degrees on the display. It gives this reading whether you just start the engine or even just turning on the ignition. My guess is the sensor is not tied to the engine network. Its a shame since these are closed cool engines and this info could indicate poor raw water flow. (raw pump, exhaust manifold, riser ect.). Are the O2 sensors a separate issue? They are known to fail. Particularly the post Catalytic sensors.