Coolant Temperature Switches / Thermo Switches

[EsperHamid]

alright so it seems Coolant Temperature Switches were dead ,,,so I bought new ones .. expensive PITA .. 20$ for each.

However .. I noticed some differences, on the old dead ones .. the black one (B)(radiator upper hose) has 106 C and the tall pink one (A)(t-stat housing) says 93 C

OLD ONES


On the new ones however ... the brown short one (B)(radiator upper hose) has "93-ON" marking and the tall grey one (A)(t-stat housing) has "90M" marking


on the Honda Service Manual it says: ECT A (BLU - BLK) (t-stat) should be ON above 90 C and the ECT B (GRN/WHT - BLK) (radiator upper hose) should be ON above 108 C

I am asking because when I first bought them, the first thing I did was to test them in a stove at home.

I realized that the SHORT BROWN one would become active when the water becomes hot and there's continuity while the GREY TALL one would become active when the water starts boiling .....though the marking on the GREY TALL says 90M while on the SHORT BROWN says 93-ON


what do I do in this case ?! which one should be hotter which one should I install on the upper radiator hose and which one on the t-stat housing ??!!

in the old dead ones case .. the tall was on the t-stat while the short was on the upper hose of the radiator

[JusAlil4Banger]

alright so it seems Coolant Temperature Switches were dead ,,,so I bought new ones .. expensive PITA .. 20$ for each.

However .. I noticed some differences, on the old dead ones .. the black one (B)(radiator upper hose) has 106 C and the tall pink one (A)(t-stat housing) says 93 C

OLD ONES


On the new ones however ... the brown short one (B)(radiator upper hose) has "93-ON" marking and the tall grey one (A)(t-stat housing) has "90M" marking


on the Honda Service Manual it says: ECT A (BLU - BLK) (t-stat) should be ON above 90 C and the ECT B (GRN/WHT - BLK) (radiator upper hose) should be ON above 108 C

I am asking because when I first bought them, the first thing I did was to test them in a stove at home.

I realized that the SHORT BROWN one would become active when the water becomes hot and there's continuity while the GREY TALL one would become active when the water starts boiling .....though the marking on the GREY TALL says 90M while on the SHORT BROWN says 93-ON


what do I do in this case ?! which one should be hotter which one should I install on the upper radiator hose and which one on the t-stat housing ??!!

in the old dead ones case .. the tall was on the t-stat while the short was on the upper hose of the radiator

Radiator fan switches A and B can only go in one spot. Thats why one has a nipple, and the other is flat. flat switch installs on front rad neck, and the nippled one installs into the thermostat housing. you cant switch them around, and switch B on the rad neck isnt really as important as switch A... depending on where and how you drive. switch B only controls the fan once the ignition is turned off. its so the coolant wont just sit there boiling in your radiator forever after you shut the car down.

[EsperHamid]

Radiator fan switches A and B can only go in one spot. Thats why one has a nipple, and the other is flat. flat switch installs on front rad neck, and the nippled one installs into the thermostat housing. you cant switch them around, and switch B on the rad neck isnt really as important as switch A... depending on where and how you drive. switch B only controls the fan once the ignition is turned off. its so the coolant wont just sit there boiling in your radiator forever after you shut the car down.

You are right .. I installed them & everything looks good now, I bled the system and the fans work as they should now .. no leaks in the coolant lines
However I am not able to set the base idle as per the DIY on cb7tuner.com .... I can hear hissing small hissing nearby the IM but not able to locate it when I remove the IACV connector the idle drops as it should be but then again " something " rises it to 850 but not in a consistent fashion... it goes up to 850 then drops to 659 .. up and down up and down ....

- FITV clean
- IACV clean
- vacuum connections look good ... but if I hear hissing it should be either from the connections or from the 7th EGR port in the IM which I replaced with a bolt glued using Alteco epoxy but doesn't seem it is the cause .. I put my ear close to it can't hear hissing maybe because of the engine and fan noises ... strangely I could easily hear the air duct near the battery even when I stand further away from it.

the hissing I am hearing close to the IM is from the driver's side.

also I am having the following light on the dashboard always ON !!

[JusAlil4Banger]

You are right .. I installed them & everything looks good now, I bled the system and the fans work as they should now .. no leaks in the coolant lines
However I am not able to set the base idle as per the DIY on cb7tuner.com .... I can hear hissing small hissing nearby the IM but not able to locate it when I remove the IACV connector the idle drops as it should be but then again " something " rises it to 850 but not in a consistent fashion... it goes up to 850 then drops to 659 .. up and down up and down ....

- FITV clean
- IACV clean
- vacuum connections look good ... but if I hear hissing it should be either from the connections or from the 7th EGR port in the IM which I replaced with a bolt glued using Alteco epoxy but doesn't seem it is the cause .. I put my ear close to it can't hear hissing maybe because of the engine and fan noises ... strangely I could easily hear the air duct near the battery even when I stand further away from it.

the hissing I am hearing close to the IM is from the driver's side.

also I am having the following light on the dashboard always ON !!

Sounds like you definitely have a vacuum leak, and/or more air bubbles in the coolant. I leave the bleeder valve open for a good long while and i attach a piece of vacuum line to it and the other end to a clear bottle. Its not always the same case when bleeding the coolant... depending what coolant line you have removed/replaced, you may have let air into other areas that make take longer to work out. but as for hissing matched with surging idle, id give the manifold a good looking.... there are a few different ways of detecting vacuum leaks. my favorite is with a tank of propane and a vacuum line(slowly feed the propane out of the vacuum line all around the manifold and wait to hear a surge) or with a lit cigarette(not as good but will help sometimes)

[HondaFan81]

I agree on the vacuum leak. Make a weekend project of replacing all your vacuum line or as many as you can get access to. These F22ax engines are aged enough, people should be replacing these type of parts and prevent occurrences such as this. Anytime I remove an IM, I replaced all vacuum and coolant lines.

I hear many talk about air in coolant system, as potential cause to issues, but that is hard to do on our F22ax engines if you do so out of bleeder screw at Tstat housing. You really have to be ignorant not do this properly.

[EsperHamid]

I agree on the vacuum leak. Make a weekend project of replacing all your vacuum line or as many as you can get access to. These F22ax engines are aged enough, people should be replacing these type of parts and prevent occurrences such as this. Anytime I remove an IM, I replaced all vacuum and coolant lines.

I hear many talk about air in coolant system, as potential cause to issues, but that is hard to do on our F22ax engines if you do so out of bleeder screw at Tstat housing. You really have to be ignorant not do this properly.

I did bleed the system properly, I filled the funnel to its quarter above the radiator neck and waited for the fans to come on TWICE !! not only ONCE .... air was purged out of the system... also I checked the coolant lines no cracks and no leaks ... however surging persists even when I remove the IACV connector !! ... what do you guys mean concerning the bleeder hole ?! I use it to bleed the cooling system then close it tight when I see a steady stream .. also I am not seeing any leaks from it .. should I cap it off any way ?! or close its screwing shat with epoxy ?!

also I replaced many vacuum lines and I'm type who sticks his head in the engine bay close enough to hear every vacuum line on the IM using my screw driver as a stethoscope ( borrowed this technique from Oyaji cool's post )

could the valve near the FITV the tiny one similar to it .. be the culprit ?!

[EsperHamid]

update: better idle

look at the engine bay .. on some coolant / vacuum / brake booster hoses I have the type of clips that have a screw on them which you can tighten .. I remember tightening these snug when engine is cold.

now that the car is running .. I thought to myself maybe they got loose because of the heat .. so I turned off the car and while hot I tightened them .... I re-started the car and it would idle at 750 rpm no surging ... I still have 2 more of these clips on the oil filter cooler ...gonna tighten them tomorrow !! ... also the oil pressure sending unit .. I remember not fully torquing it because I feared it might break and wrap the engine ... I know there's room for more torquing it was hard but not snug !!

[EsperHamid]

idle great now ..I had to tighten those screw clamps

edit:
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well after tightening those screws it idle @ 700 rpm as long as the IACV is on, once disconnected to set the base idle .... rpm stay 700 .. when inserting the iacv connector back without resetting the ecu idle goes to 1000 rpm and stays there ...ever since this car went to the mechanic to replace my dead f22a4 and I am not able to set the base idle.

when I was doing the egr tests .. I lift its diaphragm by hand to cause a vacuum, the engine stalls as it should but when I fully open it ... the engine shut off and after that I hear hissing coming from the IM area which sounds like the hydraulics of a six wheel truck...is that normal ?!