I was out tonight driving around and on my way home I noticed that my heat hand would drop all the way down and then back up to normal position. It did it quite a few times but it never once went up like it was over heating. This is the first time I have ever noticed it doing this and there is no check engine light either. If you need to know it's a '91 hb with a d15 block and y8 head. Any Ideas? Thanks

 

mine used to do that, my thermostat was stuck open so sometimes the car would acctually cool down below normal temp on a cold night. allthough my temp gauge hasen't worked for a while, since before i got a new t-stat. So... it could be somthin with the gauge itself dieng? If you lose heat when it happens or the car takes FOREVER to warm up then it could be the t-stat.

 

check the pin tension and condition of the wire on the connector to the temp gauge sending unit.
Mine did the same thing. The wire gets old, cracks, and engine vibrations will cause a bad connection to make the gauge act strange.

 

what sensor does it read from anyway?

 

^


single-wire sensor, approximately under distributor, threaded into the head.

 

if my t-stat happens to be stuck open(i'm gonna check in a little bit) is there a way to just shut it or do I need to get a new one???

 

if you closed it then your car would over heat.. its better that its stuck open then stuck shut. just replace the sucker

 

do this, this wont cost you money and you can eliminate a few variables in this problem. remove your thermostat. drive your car around, see if it still does it. if it does, its the sensor ir something related to it. if it doesnt do it, its was your thermo.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1991hb &raquo;</TD></TR><TR><TD CLASS="quote">I was out tonight driving around and on my way home I noticed that my heat hand would drop all the way down and then back up to normal position. It did it quite a few times but it never once went up like it was over heating.</TD></TR></TABLE>
If it happened repeatedly as you drove, and your heater simultaneously began blowing cold air until the temp gauge warmed up again, then your thermostat is failing. If you allow the car to sit and idle for a long time, it will likely overheat.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1991hb &raquo;</TD></TR><TR><TD CLASS="quote">if my t-stat happens to be stuck open(i'm gonna check in a little bit) is there a way to just shut it or do I need to get a new one???</TD></TR></TABLE>
If the thermostat is stuck, just buy a new one (it's under $20 including a new gasket). Don't mess with a stuck thermostat.

I would highly recommend using only an OEM Honda replacement. Aftermarket thermostats tend to be problematic.

 

ok guys here's what's up? I replaced the t-stat yesterday and the heat hand is still doing that same thing. If I'm just cruising a one speed the heat hand stays normal...when I step on the gas to get up to speed is when the heat hand goes down and than back to normal. Anymore ideas on what this can be...this is kind of weird...thanks

 

Does it do it all the time when driving or only once? What ive noticied is if i keep my eye on the temp guage, I see it fall just slightly after about 10 mins of driving. Nothing too drastic or noticeable. This is due to the thermostat opening up all the way and releasing the hot coolant from the block. It goes back up a little once the coolant has dispersed. But if the movement is very irratic and random, i'd say check the sender unit itself.

 

someone else that I talked to said it could be the sender unit also. If I go to the part store what exactly would I ask for, is it just called the temp. sending unit and approx. how much are they. Thanks