I have been having this problem ever since the ZC motor was put in about 3 months ago. When driving on the highway, or streets without many stops the temp gauge almost dosent go up at all... but if i am driving where there is a lot of stop lights the gauge will be a at the normal level (Just below half). But if I sit in very slow traffic or a long drive thur line the gauge will shoot all the way up to the top.

Many people tell me different things to do.. some say change the thermostat...Others say i have air in my coolant...Some say my sensor needs to be changed.

How do i figure out whats really the problem?



Modified by Khmi at 3:34 AM 3/24/2004

 

by process of elimination; I would bleed the coolant system, then swap in a different
temp. gauge sensor (if you have one). Check to see if your fan is coming on or not,
then check to see if your rad is full of silt & crap; the thermostat is also a prime suspect.
I had the same problem with my ZC and it turned out that the engine was full of silt & other
junk; I had to have the rad professionally flushed on two different occasions. You may even
want to swap in a different temp. gauge as well. By the way, it turned out that due to my engine
having sat around for so long the head gasket was corroded and falling apart, slowly filling
the rad with debris.


good luck.

 

Start somewhere and work your way in to find the problem, basically. With cooling systems (as well as everything else car-related), it can sometimes be hard to determine what exactly the problem is.

Start off by draining the coolant, replacing the thermostat, and putting new Honda pre-mix coolant in there. Make sure you bleed the cooling system, otherwise you will overheat. Be sure to check over the radiator and all assorted hoses while you're at it, and make sure the fans still come on. This is a cheap and safe start to determine what the problem is. Coolant and thermostat need to be replaced periodically, and they only cost about $20. Bleeding the system and checking everything over is free.

If all that stuff is good to go, then you can replace the coolant temp sender - the one that sends the signal to your dash is under the distributor I believe. Never replaced it myself, but from what I've heard, that's where it is.

If you replace the sender and it's STILL doing it, then you come back and ask more questions

Alex

 

I have never bleed/flushed the coolent before...can someone explain this process to me for a ZC. I have Changed the thermostat on my old DX motor...made a real big mess, dont want to deal with the clean up again

 

Changing the coolant is easy. On the bottom of the radiator there is a "petcock" unscrew that and all the coolant will pour out. Than once its empty just fill it up with new coolant. Run the car with the cap off until you see no more bubbles. You can squeeze the hoses to help you get all the air out. It's very easy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FourthGenHatch &raquo;</TD></TR><TR><TD CLASS="quote">Changing the coolant is easy. On the bottom of the radiator there is a "petcock" unscrew that and all the coolant will pour out. Than once its empty just fill it up with new coolant. Run the car with the cap off until you see no more bubbles. You can squeeze the hoses to help you get all the air out. It's very easy.</TD></TR></TABLE>

What about the coolant still inside the engine/intake maifold.... last time i just unscrewed from under the radiatior...though that was it...but when i when to replace the themostat coolant came spewing out every where.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Khmi &raquo;</TD></TR><TR><TD CLASS="quote">

What about the coolant still inside the engine/intake maifold.... last time i just unscrewed from under the radiatior...though that was it...but when i when to replace the themostat coolant came spewing out every where.</TD></TR></TABLE>

Exactly....what that guy is doing is a radiator drain and fill and wont do much for you at all......other then replenish your coolant but even that doesnt do much.

If you dont have a coolant flush kit and extra garden hose you'll need to have a shop do it......

Alright lets be smart guys theres really no reason why his T-stat would cause this erratic of a reading, it doesnt have that type of affect, unless his spring on it is like bent or somthing, but the ECT and thermo sensor do not read coolant flow variatons they just read temp. differences and the t-stat opening and closing no matter how fast could not cause your temp to just bounce like a bad ignitor would cause your tach.

I think its pretty obvious you've got a bad ground somwhere, I had a similiar issue like this before once.

Having air in the system is a def. possibility but then theres a good chance you wont have heat since the coolant isnt getting hot enough since it isnt really circulating do to the giant air pockets......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kasper-EF8 &raquo;</TD></TR><TR><TD CLASS="quote">

Having air in the system is a def. possibility but then theres a good chance you wont have heat since the coolant isnt getting hot enough since it isnt really circulating do to the giant air pockets......

</TD></TR></TABLE>

Yeah my heat works, but feels very weak. I Guess i am going to have to do a coolant flush tomorrow.

One question.... does anyone know where the bolt to drain the coolant from the block is at for a ZC?

 

on the back of the block next to the oil filter