Got a new one on me . As of late I''m noticing while out driving around, that my temp gauge will suddenly drop from showing a warmed up engine to all the way
cold. Drive along for a few miles and the temp goes back to normal. Checked the rad when the engine was cold and it's up full at the rad cap ,and there's
just the right amount in the over flow tank. This an indication of my temp sensor heading south I'm assuming . Since I have a oil leak on the front bank
valve cover I'll wait a bit for the weather to be right too change all at one time, but the real question is , will this temp fluctuation cause harm to the engine.
I'm thinking that it won't, but to be on the safe side I thought to ask questions here and see if any others have had this happen before /.
2015 rdx base 155000 miles

 

Most likely it is gauge acting up, but I would investigae thermostate, just to be safe.

 

Ditto. Better to be safe than sorry.

 

I was wondering about the Stat also, it's never been changed. If it became stuck open would it make the temp gauge go down to read as if the engine was cold? That's what the temp gauge is showing when it happens.
When it happens , it doesn't all of a sudden happen . I'll notice the gauge and it's like slowly happening . Might take a minute or two and then the gauge is at it's lowest point . When it goes back to normal ,
it takes a bit of time to return to normal It's not all of a sudden and flash the gauge shows cold and then all of a sudden it's normal again. I'm gonna tackle the valve cover gaskets front and back.
When I do the job , I'll replace the stat and the sensor at the same time for insurance . 72 years old and feel like I should still be turning wrenches at times, looks like this is going to be one of those times
Thanks for the replies.

 

Whats the best valve cover gasket kit for the work I'm getting ready to tackle ? Felpro ?

 

When the gauge says it drops, does the temperature of the air from the heater also drop, or does the blower temp stay constant?

 

Best I can tell the heat from the blower stays constant and doesn't change.

 

Well , I have the sensor for the temp and a new PCV vale . Anyone have recommendations for valve cover gasket , along with will I need new intake gaskets when I do the valve cover fix ?

 

I've had good luck with both Victor Reinz and FelPro. Both seem to be quality and have required no re-work.

 

Thanks for the reply. Guess Felpro will be the ones. Didn't trust the brand from what problems I had on old FE Ford engines. The ones for my 427 side oiler had a couple of bad gaskets from those folks, but I understand they finally got that problem
fixed. The gaskets for the RDX is a lot like the ones in my 530 BMW back in the day. Did you use a new intake gaskets when you did the work? The vids Ive seen didn't change them out. Would be a lot of work too make sure
nothing got down the tubes, but would thinks it would be safer to make the change while in there. At 72 years I havn't wrenched in a few years , so I'll drive my pickup and take my time with this project.

 

Well I've found that the temp sensor was the culprit. I replace the sensor along with the PCV valve yesterday and all is well. The engine before the sensor was replaced, I noticed there was considerable amount of time before the engine temp came up
on the gauge in the car. Now the temp comes up like I think it should. The sensor looked rough along the point that is submerged in the engine block,,real rough ,Anyway, the sensor has solved that problem, now will wait a bit and do the valve cover gasket.
Just thought to report back.

 

So why is your sensor looking so bad? You said your car has 155K miles so the timing belt/water pump should have been changed out at ~100K. Done correctly, this maintenance includes draining the radiator so you get most of the old coolant out and get new HONDA coolant (blue) back in. Did your shop change the radiator fluid? Antifreeze can start to turn acidic after 5-6 years.

 

Timing belt service was at 92,000 miles. I had the work done early along with the water pump and the service should have included the replacement
of the coolant. Anyway the temp sensor was very rough feeling , not smooth as the replacement . Thought having the work performed a little
early was good insurance. Will have to make sure they do the total replacement of coolant on the next belt change.

Above you mentioned that the coolant can go acidic over time , I agree with that . Question would not the time or aging of the collant
also be taken into account the amount of miles put on the vehicle , along with the time line ? Reason for asking, I purchased a 2011
Toyota Tundra from a friends estate sell recently. The truck was never driven much and only has 25,000 miles on her. Guess
I might need to have the coolant flushed and changed there also..
. .