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I have utilized Yotatech members knowledge for years when troubleshooting, fixing, and maintaining my Toyotas. Thank you all! Purchased 1990 Pickup/5 speed. A few days into ownership, leaking coolant after replacing radiator, cap, and thermostat. Turned out it was u hose on coolant sensor block. Replaced it, and the rest of the coolant hoses, oil cooler hoses and seals/gaskets. Pressure tested and found leak - lower intake manifold gasket passenger side. Once reassembled: pressure tested - 10 minutes, all good. Fired her up, burped and she’s been running great - zero pinging, great heat, great idle!
Every Toyota I own/have owned, temp gauge sits at or darn close to the middle of the gauge. This truck runs great, heater works great, and the gauge sits where it sits in pic after warm up, stop and go traffic and at highway speeds. Should I be concerned with the temp gauge where it is? Normal on 3vze?
After 10 minutes.
Last edited by Carolina3slow; 11-12-2018 at 05:51 PM.
Suggest connect a separate and reliable temp gauge for alternate reading and compare? It has been suggested I may want to switch to a different grade oil, I currently use a 10/30 grade?
Recently had 90 T4r 4x4 w/ 3vze and 210k miles rebuilt but before taking it to the shop the temp gauge hovered around the very low mark at idle then moved into the normal range at higher rpm. After the rebuild I noticed the oil temp gauge was reading the same as before and when I questioned the shop owner, apparently the low reading was an issue because after the rebuild the owner hooked up a separate temp gauge and took a video showing the oil temp running closer to the normal range, I was not present but accepted the video. It has now been approx. 14 months and all accessories are working normal; A/C, Heater, etc. with no over heating or engine issues.
My gauge reads more left of center, by the lines representing coolant, then yours. My cooling system was recently gone through (hoses, thermostat, radiator, etc.), too. I'm running a 195 degree thermostat.
Measure the resistance on the sender from the prong to the body/shell, compare this with the prong to the mount. If it's not almost identical your sender doesn't have a good ground.
Repeat testing at the body ground strap to the battery. Repeat as necessary for other ground connections..
The only real concern about a dash gauge reading a lower temp is when it gets near to hot and could be reporting a temp you think as not hot enough you would worry about it but be ready to boil over..
I purchased a new sender a few days ago and have not installed as I wanted to test first. I did test sender wire, grounded and it pegged immediately. You are spot on regarding “boil over” - I’ll test sender. My concern is all my Toyotas, past and present, ran near the middle.
Last edited by Carolina3slow; 11-10-2018 at 05:01 PM.
My gauge reads more left of center, by the lines representing coolant, then yours. My cooling system was recently gone through (hoses, thermostat, radiator, etc.), too. I'm running a 195 degree thermostat.
My gauge reads more left of center, by the lines representing coolant, then yours. My cooling system was recently gone through (hoses, thermostat, radiator, etc.), too. I'm running a 195 degree thermostat.
My gauge sits about midway also once it's up to operating temp and rarely moves off that point, it's so reliable that I've questioned its accuracy in the past but Larry at Yodaman assures me that it's perfectly normal.
... I did test sender wire, grounded and it pegged immediately. ...
uh, oh.
You should never test a gauge by grounding the sender wire, you should only connect it to ground through a suitable resistance (the FSM recommends a test bulb). http://web.archive.org/web/201102052.../6combinat.pdf You CAN test an idiot light by grounding the wire.
Ordinarily, grounding the sending wire will permanently damage the gauge (those who do combination meter swaps from idiot light to gauge, but forget to change the sender, find this out the hard way). With luck, you may not have grounded your gauge long enough to damage it.
Ouch, I hope you are correct and I didn’t damage it. I am assuming, no, as it is doing the same thing it did before testing. I think I’ll check thermostat tomorrow and eliminate the stuck open possibility and go ahead and install the new sender.
Ouch, I hope you are correct and I didn’t damage it. I am assuming, no, as it is doing the same thing it did before testing. I think I’ll check thermostat tomorrow and eliminate the stuck open possibility and go ahead and install the new sender.
Three perfect examples of what not to do in a single thread..
Do not touch wires to things unless you really really know what you are doing.
Do not shotgun parts at a problem. (Oh but my new part fixed it.. Did it really or did you just need to tighten that connector another mm..)
Start the engine with the radiator cap off, is the coolant flowing. The answer you want is no because the thermostat is closed.
Put your radiator cap back on. Wait for the guage to move from its rest position. Now touch the radiator hose is it warm. Your thermostat opened. Still not sure start it cold without the cap wait about ten to fifteen minutes with the cap off and you should see the flowing coolant.
Unless you are testing to verify the thermostats opening temperature there is no reason to go thru all that draining removing replacing resealing refilling.
Again test don't guess. My money's on a bad connection either the sending unit wire to.sending unit or the manifold ground..
The sending unit has a range of something like 100ohms(125/25, cold/hot) any connections that add as little as five to ten ohms are going to have a large effect on the guage reading. There are five or six of these in the ground path after the sensor, now we're down to as little as one ohm added for each connecting point having a notable effect..
Do your other guages seem off abit? That would be a cluster or body ground.
Appreciate the response. Correct, not confident with electrical. I should have referred to manual as I do have Agreed, the thermostat is likely not the issue. Truck runs well, just don’t want a false reading. The other gauges do not seem off. I’ll read up on testing and check out the ground. Thanks.
Last edited by Carolina3slow; 11-12-2018 at 05:52 PM.
... Do not touch wires to things unless you really really know what you are doing. ...
"really, really"? Ow, I guess that leaves me out.
To be fair, it sounds like Carolina thought he knew what he was doing. He read that you could test a temperature (something) by grounding the wire. Which is correct if you're testing a temperature switch that connects to the Idiot Light.
The good news is that he's working with 12volts, so it's hard to kill oneself. (If we're talking about a 12kv Recloser, then that advice is gospel.) He might have damaged the gauge, in which case it's a costly lesson learned. (compared to the cost of other lessons I've learned, actually pretty cheap) And we all have to start somewhere.
I made my post not so much as to warn Carolina (that would be too late), but if someone else peruses this thread, they'll get something to consider.
11-09-2018, 05:11 PM
