i have a91 k5 and every now and then it runs sluggish and my temp gauge stays on 160.it will do this for a week or two then it goes right back to 190/200. its been doing this for 2 months now and it pisses me off i can tell a difference when i take off from a green light look down and my gauge reads 160.then a week or a day or a month later i notice more pep in the take off i look down and my temp is 190.i know when the engine is cold it dumps more fuel (killing gas millage)but i cant figure out why.my gauge is accurate i have replaced the senor on top by the intake and the one on the block by the sparkplug and the contacts are clean .does anyone have an idea???????? could this be some sort of computer problem?help!! thanks
CK5
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91 k5 running rich...only gets 160 on temp????
- Thread starter j everett
- Start date
Replace your thermostat w/a new 195* one.
Doesn't mean it can't be bad. There are too many cheapo t-stats out there these days. Buy a good quality t-stat of the 195* and make sure it's installed correctly (spring side down into intake manifold). Seen a few people install them upside down.
So did the temp test tell you the gauge is accurate?
If it did, the thermostat is bad, period.
If it did, the thermostat is bad, period.
Too many people come here to ask for help and then don't listen to the advice given. 
Don't be too hard on new folks...gotta remember, many people don't have the background some do, nor the luxury of having sat on various automotive sites for so many years to know what we consider common problems, or telltale symptoms.
Pertaining to this post, many people with plenty of experience still consider new to mean that something is good. Not everyone takes advice the same way. My sister is a prime example....I end up telling her "you ask for my advice, but you still do whatever you want anyways". All you can do is offer advice, it's the recipients choice to take it or not.
Pertaining to this post, many people with plenty of experience still consider new to mean that something is good. Not everyone takes advice the same way. My sister is a prime example....I end up telling her "you ask for my advice, but you still do whatever you want anyways". All you can do is offer advice, it's the recipients choice to take it or not.
To be honest, i did not even pay attention to him being so new on this site. Hopefully though, he'll do alot of reading on here and find out who the knowledgeable people are.
Attitude and post count are two of the things I use to determine my interest in attempting to help.
(don't read that wrong, just that if someone has been around awhile and obviously ignores info given, I'll not waste anymore of my time)
(don't read that wrong, just that if someone has been around awhile and obviously ignores info given, I'll not waste anymore of my time)
This part makes me think it's a bad sensor or wiring problem. A thermostat that is weak can keep the engine cold, but physically speaking you can't change the temp of the coolant and block very quickly.
has anyone else experienced this or are these replies from shadetree mechanics?if the thermostat was bad (stuck closed)you couldnt feel the water in the return hose,if it was stuck open then it would send water back to radiator immediately on start up, i hit the block with the laser watching it warm up when it gets to 190 you can see on the laser when the thermostat opens i also felt the hose
Whoa dude, you're here asking for help. We are giving our advice (our replies are from knowledgeable people). Had you mentioned earlier about using a heat gun to check then i'm sure we wouldn't have went with the t-stat comment. I'm with Dorian, i'm going to back out of this thread now.
i dont mean to be an asshole, i just took offense to the not listening to advice remark.i will definitely listen. im just sure its not the thermostat.thats the first place i went 3 times.im just a little frustrated and at the time i felt the not listening remark was belittling
Well, you might want to check peoples profile before you start asking if these are "shadetree mechanics". I've been working on cars for 30 years now, i don't know everything (nobody does) but i do know a hell of alot to consider myself more than a "shadetree mechanic". I know how it can be frustrating sometimes when you can't figure out a certain problem but don't take that anger out on people that are giving you advice and trying to help you even though you may have already tried the advice that was given. By the symptoms you're having it just relates to a t-stat problem.
So again, did the IR thermometer confirm that the temp gauge is correct, that the engine does actually jump up to 190*, then go to 160*, or not? You say it jumps...even with a completely shut thermostat, it would take awhile to gain that 30*. Does the gauge actually jump (I'm talking 30* in a second or less), I do agree that it's not likely the thermostat.
And on the shadetree part, using the term "shadetree" anymore IMO usually means that the person is more qualified and experienced than someone who is paid to be a mechanic. So more of a compliment, except when intended to be used in a derogatory way. Especially on forums, you get people who are intimately familiar with these particular vehicles...many mechanics have to deal with a broad range of vehicles and are more generalists.
The longer you are around, the more you'll see it. "Real" mechanics anymore, for the most part, are parts changers, and most will throw parts (at your expense) towards a problem until getting lucky, you are broke, or they can't throw anymore parts at it and give up. It's not all, but from what I've seen, it's very, very prevalent. So don't think you aren't getting good advice because someone isn't a mechanic. Also don't believe everything you read, anywhere.
And on the shadetree part, using the term "shadetree" anymore IMO usually means that the person is more qualified and experienced than someone who is paid to be a mechanic. So more of a compliment, except when intended to be used in a derogatory way. Especially on forums, you get people who are intimately familiar with these particular vehicles...many mechanics have to deal with a broad range of vehicles and are more generalists.
The longer you are around, the more you'll see it. "Real" mechanics anymore, for the most part, are parts changers, and most will throw parts (at your expense) towards a problem until getting lucky, you are broke, or they can't throw anymore parts at it and give up. It's not all, but from what I've seen, it's very, very prevalent. So don't think you aren't getting good advice because someone isn't a mechanic. Also don't believe everything you read, anywhere.
For what it's worth, I'm an ASE and Nissan master technician with 15 years dealership experience. I have seen t-stats do exactly what you are describing, but since you are positive it's not that then you have to ask yourself this, why would the temp guage and the computer both see the engine running 160* if it wasn't actually at 160*? They use different sensors. The temp guage uses the one wire sending unit in the left head and the computer uses the two wire sensor in the intake manifold. 
