Temp sending unit--or something else?

[Turdle]

I have 2 cylinder head temperature gauges installed in a dash pod. The senders are located in the rear head bosses--against the firewall. They are located as such that to get to them requires pulling the engine, I do think

In fact, I had bumped the passenger side sender against the fiirewall when I installed the engine and always suspected it, as it read about 5 degrees higher than the driver side .

Now, today, out of the blue--
Idiot gauge in cluster reads as normal, just into the n range. Driver head reads 170 or so, but the right side reads 220, maybe even higher.

So, When I returned from the 25 mile round trip, I let the engine cool and started it gain to observe the gauges from a cold start.
Just as soon as the driver side gets a reading,150 or so, the passenger side is shooting up to 190.

I have an infrared handheld thermometer, where should I point it for a reading to compare temps from bank to bank, without header temps interfering with my reading?

Or do you have a better suggestion for troubleshooting this??

I almost wish I didn't have these gauges now--

 

[CDW6212R]

Did you place those in the back head holes, I thought that you had an EGT sensor? Are you reading the temps of the head, steel? I'm pondering whether to install two or three on my pillar, or one on the column and two on the pillar.

Use something to protect the hand held tester from the header heat, a thin board or cardboard etc. What thermostat do you have?

 

[Turdle]

Did you place those in the back head holes, I thought that you had an EGT sensor? Are you reading the temps of the head, steel? I'm pondering whether to install two or three on my pillar, or one on the column and two on the pillar.

Use something to protect the hand held tester from the header heat, a thin board or cardboard etc. What thermostat do you have?

It is a 180 degree

The senders are in the metal--yes. No coolant touches them.

I never did go with a EGT sensor. I do have a meter now, and a source for probes though to get one working . I think I mentioned that to you.

 

[CDW6212R]

What does the infrared heat sensor show? That should be more reliable than two separate sensors. Hopefully one is not working right, do those work on voltage as older digital gauges did? My first digital gauges were almost useless, I had added switches and extra wire to them.

 

[Turdle]

What does the infrared heat sensor show? That should be more reliable than two separate sensors. Hopefully one is not working right, do those work on voltage as older digital gauges did? My first digital gauges were almost useless, I had added switches and extra wire to them.

These are a simple one wire sender-

I think I may compare cold resistance between the 2 also

 

[J.A.F.E.]

Could you try switching the guages?

 

[Turdle]

Could you try switching the guages?

That would not eliminate an overheating head-or sender issue.

Thanks though for the idea. It would be a way to determine if the gauge itself was faulty.

 

[Turdle]

Ok, first, I keep my cooling system very clean. I see now way I could have a coolant flow problem to the bank 1 head.

Is there an issue I am unaware of?

I ran the truck for at least half an hour this am, took my son to school and even drove at highway speeds for a minute-the bank 1 gauge never did indicate higher than 210 degrees, however the bank 2 gauge did stay at 190 or so.
I would think if there was indeed a cooling issue, I would have blown a head gasket by now

Ideas for me?
I am supposed to make a 7 hour trip tomorrow AM and this has me a bit nervous to say the least.

Should I just ignore the guage?

 

[Cobraguy]

First JT, 210 to 220 with a pressurized system is nothing to worry about. You are not overheating anything. But since you really aren't measuring water temp, it does concern me some. I am assuming these sensors read the actual metal head temp by being attached to the head with an accessory mount bolt hole. In that case, do you have an air pocket in that cylinder head? Is your radiator completely full and the puke bottle level going up and down with engine temp? That is a good indication of whether or not your cap is still good. But you know all that I'm sure.

I have a Fluke meter that actually has a temp probe that can be attached. The probe can be an actual metal probe or a wire. You could attach that probe to your head with tape or something and take a reading against your gauge reading.

Are you certain you can't remove the sensor without pulling the engine? There is a bit of room back there. It would be a real ***** to get to for sure, and you may have to bend a wrench to get something to work, but it appears to be possible. How about if you went through the wheel well for hand access? And you could always pull the evap case. Ugh. But that isn't a difficult job really. You just have to open the a/c system which sucks.

Finally, if you suspect a head gasket leak, you could always do a leak down test or have someone sniff the radiator for exhaust. What head gaskets did you use when you put it together? If you used the good Felpro gaskets, I would be shocked to see a gasket failure. Those just don't fail when properly installed.

 

[Turdle]

First JT, 210 to 220 with a pressurized system is nothing to worry about. You are not overheating anything. But since you really aren't measuring water temp, it does concern me some. I am assuming these sensors read the actual metal head temp by being attached to the head with an accessory mount bolt hole. In that case, do you have an air pocket in that cylinder head? Is your radiator completely full and the puke bottle level going up and down with engine temp? That is a good indication of whether or not your cap is still good. But you know all that I'm sure.

I have a Fluke meter that actually has a temp probe that can be attached. The probe can be an actual metal probe or a wire. You could attach that probe to your head with tape or something and take a reading against your gauge reading.

Are you certain you can't remove the sensor without pulling the engine? There is a bit of room back there. It would be a real ***** to get to for sure, and you may have to bend a wrench to get something to work, but it appears to be possible. How about if you went through the wheel well for hand access? And you could always pull the evap case. Ugh. But that isn't a difficult job really. You just have to open the a/c system which sucks.

Finally, if you suspect a head gasket leak, you could always do a leak down test or have someone sniff the radiator for exhaust. What head gaskets did you use when you put it together? If you used the good Felpro gaskets, I would be shocked to see a gasket failure. Those just don't fail when properly installed.

Well, in the past--
like the 15 hour trip we went on to Co last fall, or, the trips 2 hours to Wichita we have just made, I have never seen either gauge read this high. I did see these temps while climbing steep inclines in the mountains--

This is why I am questioning it. I mean, it was like a light switch had been turned on and now this one gauge is way high in it's reading.

These have been installed like this for about 4 years , if not longer.

Thanks for the help!!!!

 

[410Fortune]

It seems to me after working on many of these 5.0L's that the drivers side of the engine is relatively open and the passenger side is packed in tight with EGR and the heater / ac box
The pass side head also has the heater core hoses flowing on top of it (taking up airspace) and the throttle elbow, and egr mounted behind it, not alot of opportunity for air flow LOL

maybe this attributes to why it was always 5 degrees higher on that side and your sender has always been fine?

Hows it running?

gages can be a PITA, lol cant take your eyes off of them when you think there might be an issue, not many people would be aware one head is 15 degrees hotter! LOL just keep driving..

access to the back of the head is not as bad as access to the back of the block

 

[Turdle]

It seems to me after working on many of these 5.0L's that the drivers side of the engine is relatively open and the passenger side is packed in tight with EGR and the heater / ac box
The pass side head also has the heater core hoses flowing on top of it (taking up airspace) and the throttle elbow, and egr mounted behind it, not alot of opportunity for air flow LOL

maybe this attributes to why it was always 5 degrees higher on that side and your sender has always been fine?

Hows it running?

gages can be a PITA, lol cant take your eyes off of them when you think there might be an issue, not many people would be aware one head is 15 degrees hotter! LOL just keep driving..

access to the back of the head is not as bad as access to the back of the block

yeah-
it always did read a bit higher-but I attributed it to when I bumped-and bent, the sender.

 

[Turdle]

Well,
Hmm, I was poking around and discovered my valve cover gasket leaking a bit-and oil on the sender-
since it was bent ( and cracked a lil' when I bent it back lol ) I would betcha some oil got into it and messed it up a bit.

I gave the valve cover bolts another trun all the way around. They were a bit less tight than I remembered.

My infrared actually shows the passenger side valve cover as being 10 degrees cooler than the driver side--

I'm just going to load up and drive this sucker--

 

[CDW6212R]

I would rely on the water temperature readings from the PCM as much as possible. If the water doesn't get past say 210-220 I wouldn't hesitate to drive it. If the condition around one or two cylinders was much off, that should affect the way it runs, gas, water usage, or some symptom. If worried do a leak down test, and/or the coolant testing. Fingers crossed for you,

 

[Cobraguy]

Well,
Hmm, I was poking around and discovered my valve cover gasket leaking a bit-and oil on the sender-
since it was bent ( and cracked a lil' when I bent it back lol ) I would betcha some oil got into it and messed it up a bit.

I'll bet you money that's it JT! Fresh oil would be hotter than your coolant...old oil might just screw it up. Did you see if you could find a way to replace the sender while on the car?