Overheating and loosing coolant (leak), 2010 crv
 

Hello, everyone.
This is my first post.
The problem - smoke from an engine bay, smells like coolant.
Observation - low coolant in the radiator, higher than normal engine temp (about one notch over the middle - used to be about 25-30% of the gauge), low engine oil (just below "low" mark, wet radiator (back side near lower radiator hose and lower part of fan), smell in the cabin (coolant?), coolant expansion tank is dry.
CEL light is on. VSA OFF light is on. Error codes: P0117 (ECT sensor circuit low input), P0171 (lean condition), 83-1 ECM/PCM relation failure.
Added about 1/2 gallon of new coolant and about 3/4 qt. of motor oil.
Upper hose temp 185F, lower - 140F.
When engine is warm, the coolant started to spray from underneath of plastic intake manifold, almost in the middle, just to the right and above lower radiator hose. The coolant sprays in about 1 second intervals. When engine is shut, the coolant sprays more liberally (with noticeable hissing) for a few seconds.
Stats: 2010 CR-V with about 180K miles. Original cooling system components. O2 sensor was replaced about 20-50K miles ago (Denso).
Short and long term trims are high - about 23%. I cannot get a live data on this car with my scan tool.
link to a video: https://cloud.degoo.com/share/B8k3BS6YCQs_yLzkI-uWFQ

I suspect some gasket underneath intake manifold.
I deleted error codes and ran engine for a few minutes - no new/repeated codes...

EDIT: thermostat housing?

I would pressure test the system and find all leaks. You'll at least need to take the manifold off and seal it.

I looked "closer" and saw a rusty metal pipe, which runs from a thermostat body (back portion) up and right (beneath intake manifold) to, I guess, a heater core.
https://www.hcrv.net/images/books/16...cement_526.jpg

It's indicated on the diagram above as C.
Here are pictures:

https://cimg4.ibsrv.net/gimg/hondafo...beec96a456.jpg
https://cimg2.ibsrv.net/gimg/hondafo...ee3c34c791.jpg
https://cimg3.ibsrv.net/gimg/hondafo...6838794cda.jpg

EDIT:
If that rusty spot is a cause of a leak, then it may "match" the area where coolant sprays (on the video).
Am I on the right path (without pressure testing the coolant system)?

This is a part I question:
https://cimg5.ibsrv.net/gimg/hondafo...8bf1995f17.jpg

That definitely looks like a leak.

Additional question:
ON my video, coolant sprayed in pulses with running engine and sprayed in one long burst after shutting the engine off. In my understanding the pulses were the result of pressure build-up while coolant was circulating. Why was it pulsing?
Also, I just leaned that the "Honda's" proper coolant flow is from bottom hose up the radiator (hence thermostat is in the lower hose). In the rest of the world the flow is from top to bottom. Nevertheless, top hose temp was 180F and bottom was 140F.
Temp. sensor is located at the bottom of radiator. So. I suspect that the thermostat doesn't work well anymore. I don't know how the thermostat is designed. Most fail and are shut closed. Some (better in my opinion) are open when failed.
So, the top radiator hose was getting hotter and hotter, thermostat was closed, temp sensor indicated high temp, hot coolant was venting out and, as a result, 1/2 gallon of coolant was vented out. That would explain coolant loss, wouldn't it?

It's from the thermostat opening and closing.

I see. thanks.
BTW, that heater pipe is out of stock with unknown availability date...of course!!!
I think, that it'll be wise to replace a thermostat (assembly) while I'm tinkering with cooling system...
Will post back with the results.

update:
The heater pipe is replaced.
I also added a rubber sleeve so any elements would not collect on top of Thermostat Housing heater outlet and let the heater pipe rust.
Honda's engineers didn't realize, or didn't want to, that steel usually rusts. To compare, my other 35-year-old car has a similar heater pipe, which is MUCH thicker zinc-plated pipe and without any rust.
Below are the pictures of old part and other related pictures.
Temperature gauge was 2/3 when I noticed this leak (the pic below shows only 1/2:

https://cimg8.ibsrv.net/gimg/hondafo...4b3bfcf27a.jpg


https://cimg4.ibsrv.net/gimg/hondafo...be7450b972.jpg
https://cimg5.ibsrv.net/gimg/hondafo...17bf101ee6.jpg
https://cimg0.ibsrv.net/gimg/hondafo...3046169cce.jpg
https://cimg1.ibsrv.net/gimg/hondafo...f1506e5729.jpg

To lessen any future corrosion, I panted a new heater pipe with rubber paint:

https://cimg5.ibsrv.net/gimg/hondafo...a640355fe8.jpg

Added rubber sleeve:


https://cimg8.ibsrv.net/gimg/hondafo...73f8a7d059.jpg
https://cimg7.ibsrv.net/gimg/hondafo...ecdf3b1eb9.jpg



Note:
all rusty hose clamps were replaced with S/S ones.
All is done, car behaves normally, temp gauge stays just over 1/3.
What bothers me is a left-over screw and I don't know where it came from. Could be from somewhere underneath a plastic intake.... but I just don't remember.... Here it is:

https://cimg5.ibsrv.net/gimg/hondafo...fa9ec7d586.jpg

Glad you got it fixed.