LB7: temp gauge sensor install?

[THEFERMANATOR]

When I did my swap, I neglected to install the coolant temp gauge sender into the block(one of the many oversights when I did my swap), so I installed it in a T in the heater hose line coming out of the t-stat housing. This has worked fine for all these years, but I have decided I want to improve my A/C by installing a heater valve to shut off coolant flow to the heater cores(my control head has the trigger to install one, so it's a fairly easy job). My problem is I want to go with a 2 port valve as I don't have alot of room to install a 4 port valve. If I go to a 2 port valve, this will stop the coolant flow across the sender in it's current location. Is there a spot in the heads that can be fairly easily drilled and tapped to install a temp sender? When I did the swap I didn't see any pipe plugs in the heads or block to screw the sender into, but it's not to say I missed one. Otherwise I will have to figure out how to squeeze in a 4 port heater control valve which will mostl ikely involve going to a van fuel filter housing remote mounted somewhere(I'm one of those wierdos who still likes the OEM fuel filter as the final filter).

 

[rfletes79]

We tapped the block off plate on the adapter plate passenger side (belhousing area). The plate comes right off, 2 bolts. Drill and tap and your golden

 

[JoshH]

Why not drill and tap the top of the thermostat housing?

 

[Duramax One]

Why not drill and tap the top of the thermostat housing?

Good idea. IIRC, there should be room behind (toward the rear of the truck) the factory temp sensor. That will also get you the most accurate engine temperature reading.

 

[rfletes79]

Why not drill and tap the top of the thermostat housing?

If the thermostats ever fail and get stuck closed then you'll have an inaccurate reading from the top side of the housing.

 

[JoshH]

If the thermostats ever fail and get stuck closed then you'll have an inaccurate reading from the top side of the housing.

That's true. I guess I don't understand what's wrong with the factory location. I would rather see the temperature after all the heat load.

 

[Duramax One]

If the thermostats ever fail and get stuck closed then you'll have an inaccurate reading from the top side of the housing.

I was thinking of tapping it next to the factor sensor, which reads the engine side of the thermostat, not the output side. Of course, I'm basing this off memory here, so there may not be any room.

I'm not sure what the odds are of both thermostats failing closed, but hey, why not play it safe?

You could always try tapping elsewhere on the coolant crossover tube (the one that houses the thermostats). There's also the option of trying to pull the temperature from the back of the heads. There are two freeze plugs in place of the thermostat crossover tubes on the back of each head.

We tapped the block off plate on the adapter plate passenger side (belhousing area). The plate comes right off, 2 bolts. Drill and tap and your golden

The reason I'd be hesitant to get the temperature here is that the coolant at this point has not passed through the heads, which is where a majority of your heat load comes from.

That's true. I guess I don't understand what's wrong with the factory location. I would rather see the temperature after all the heat load.

I suspect he is using the factory sensor for engine management purposes and the factory Suburban sensor to provide the gauge reading.

 

[rfletes79]

I believe he is using a seperate gage, not related to the oem harness or ECM. Just my guess.

 

[rfletes79]

Head load, got it. May have to move our sensor.

 

[THEFERMANATOR]

The stock CTS is still there and is plumbed to the ECM. I'm using my 95 cluster which uses it's own 1 wire sender. Currently it is in a grounded T mounted inline in the heater core feed line, and has worked fine. I'm just wanting to put in a heater control valve to try and get a little better A/C in this 95-100 degree heat we have had here as of late. I should have drilled and tapped the t-stat lower housing when I last had it off. I thought about doing the passenger side plate, but was concerned it might read low since it is in the incoming coolant stream from the radiator. I also considered knocking one of the welch plugs out of the heads, and seeing if I could tap it to 1/2" pipe and reduce it down for the sender.

 

[Chevy1925]

from what im seeing as to how your heater core and evap are separated, i highly doubt you will notice much difference and if you do, its going to be very minor for all that work. you really need to look at your fan clutch. without that thing pulling that extra air across at idle when hot like you stated in Adams thread, i can bet your high pressures are up there and that little electric fan just cant keep up.

 

[duratothemax]

2007.5 to early-2009 LMM's actually have two coolant temp sensors. Both mounted right next to eachother on the t-stat housing.

 

[JoshH]

2007.5 to early-2009 LMM's actually have two coolant temp sensors. Both mounted right next to eachother on the t-stat housing.

They also don't pull coolant for the heater core/EGR cooler from the thermostat housing.

 

[THEFERMANATOR]

from what im seeing as to how your heater core and evap are separated, i highly doubt you will notice much difference and if you do, its going to be very minor for all that work. you really need to look at your fan clutch. without that thing pulling that extra air across at idle when hot like you stated in Adams thread, i can bet your high pressures are up there and that little electric fan just cant keep up.

I don't have problems at idle since adding the 10" electric fan to the condenser(high side pressure rarely sees more than 250 now, but without the elctric fan it would hit 375). The only tme I have trouble is when towing, and engine temps get over 190, then the A/C is slightly lacking running on outside air. The GMT-400 evap housing left ALOT to be desired, and GM factory installed heater control valves on a few years because of it. When running empty and engine temps are 185, I can freeze anybody out of it. But on a 98 degree day and engine temps running 205-210 is another story. A/C is one of my things I'm pretty good at(used to be certified master and all that stuff before I let them expire), just after a little better performance from it. And with my OCD, I tend to overdo things a bit like this.

 

[Chevy1925]

I don't have problems at idle since adding the 10" electric fan to the condenser(high side pressure rarely sees more than 250 now, but without the elctric fan it would hit 375). The only tme I have trouble is when towing, and engine temps get over 190, then the A/C is slightly lacking running on outside air. The GMT-400 evap housing left ALOT to be desired, and GM factory installed heater control valves on a few years because of it. When running empty and engine temps are 185, I can freeze anybody out of it. But on a 98 degree day and engine temps running 205-210 is another story. A/C is one of my things I'm pretty good at(used to be certified master and all that stuff before I let them expire), just after a little better performance from it. And with my OCD, I tend to overdo things a bit like this.

Your still talking about a fan issue. You said your self the fan doesn't kick on till after those temps and by that time your heat soaking the condenser more than outside air can cool at highway speed (and more than likely that electric fan can push). My tracker did it and my truck is starting too due to the fan dieing. In the temps out here, when you first start a mechanically driven fan vehicle (older vehicles now a days), kick the a/c on and drive at city speeds, the a/c blows half ass cool until the motor/condenser finally get hot enough to kick the fan on. Cracking windows, switching to outside air and a/c on helps for cooler air quicker but the fan really brings the cool. Kinda rambled but point is, that fan makes a big difference in the a/c with as much air as they move and you hit triple digit temps. Over 105, you gotta have your a/c dialed in for decent air.

 

[malibu795]

How big cfm wise is that 10" fan? I got a pair of Jegs 1000cfm 10" on my oil coolers..
http://www.jegs.com/webapp/wcs/stor...tId=1031489&storeId=10001&sType=&pgGrp=search
Upgrading my coolers (setrab 640x2)and fans...pull version of this...
http://www.racerpartswholesale.com/product/2113/SPAL_Fans_33

 

[THEFERMANATOR]

i doubt the fan clutch is an issue at 70 running down intetstate. when i slow down the ac gets colder due to the coolant temp dropping. the evap in my burb was a marginal design at best by todays standards as many have the same complaint i do. im just trying to figure out how to add in a heater valve which gm factory installed in many of these as the ac control head already has an output for it. the thing is for electric cutouts, most are only 2 port. so i have to move the coolant temp sender from my current location to install one of them.

 

[Chevy1925]

i doubt the fan clutch is an issue at 70 running down intetstate. when i slow down the ac gets colder due to the coolant temp dropping. the evap in my burb was a marginal design at best by todays standards as many have the same complaint i do. im just trying to figure out how to add in a heater valve which gm factory installed in many of these as the ac control head already has an output for it. the thing is for electric cutouts, most are only 2 port. so i have to move the coolant temp sender from my current location to install one of them.

again, still points to a fan

 

[THEFERMANATOR]

again, still points to a fan

A bad fan clutch would heat up at slow speeds, not cool down. At slow speeds is when the fan clutch is doing all the work to cool the engine, and at speed ram air does most of it. My AC issue is COMMON to this model of truck, and GM even installed a heater control valve to help with it for a few years. My control head is already set up to control a heater control valve, but I didn't install one since I no longer have a vacuum system. I know my swap has compounded the issue due to the proximity of the engine to the accumulator and some other issues I ran into doing my swap. Just trying to improve the system to make it a little better. I can still switch it to inside air and stay COLD inside, just would like to be able to stay cold with it on outside air towing.

 

[Chevy1925]

Lol ferm, you told us in another thread that fan won't fully lock or kick in till above the temp your having issues at..... And your only having issues between those temps..... You really think they don't coincide? I didn't say the fan won't work at slow speed, all I said is it was a fan issue. To be specific, it's not kicking on earlier enough.