2003 150TXRB Overheating

[FishEdStu]

2003 150TXRB overheating. Taken to shop and they did a complete water pump change. During their test run the motor overheated again. They said that the infrared was reading hot by the thermostats. I'm thinking that I may need to take off heads and head covers to see if water passages are clogged. Besides also checking the poppet valve, is there anything else I'm missing? I appreciate the help.

Edit: wanted to add that alarm went off and that is when i noticed there was nothing coming from tell tale.

[99yam40]

what about testing or replacing the stats

[FishEdStu]

99yam40 I plan on replacing the stats as part of my teardown and rebuild.

[99yam40]

if you pull and test them before you tear down the rest,
it may keep you from having the pull the heads if you find a problem with the stats and PRV

[FishEdStu]

99yam40 I will definitely do that prior to anything else then. Thank you for your input.

[pstephens46]

Wonder why the shop didn’t check the obvious?

[DannyMart]

You could try running a solution to dissolve the calcium carbonate build up in the cooling passages before pulling the heads. After 17 years, the risk of breaking bolts is real.

https://www.amazon.com/Hammerhead-Ma.../dp/B01JQZIJJI

This stuff WILL dissolve calcium.

https://www.youtube.com/watch?v=R_3IS4QV_nQ

[FishEdStu]

So after all was said and done I ended up pulling the heads and found an extreme amount of blockage. Cleaned out as much as possible and then soaked in vinegar solution. After cleaning, installing new gaskets, and checking everything over she fired right up. Test ran it and everything is good. No overheat condition and using an infrared thermometer I have verified that the engine is running good. Thank you to everyone that wrote in.