I have a 95 Vette. I have owned less than a week so going on the previous owners ideas. It supposedly gets hot in traffic... For me it's not a daily driver and for a nice secondary car it's great. I wanted to check the cooling system first. I pressurized up to 15 lbs and it held great. i checked the radiator cap and it worked as it should. the one thing i have noticed, is that when running it doesn't build higher than 7 lbs pressure....even when revving the engine...

Any ideas guys..I am thinking thermostat or waterpump.

 

We need numbers. More than "gets hot in traffic."

 

Before you start swapping parts, you need to search around this section for all those before you with the same problem.

Overheating, radiator blocked, purging, burping..... etc.

 

Check to make sure the fan is working right.

Also one place most people fail to look is to check to make sure heater hoses are not crimped or clogged, etc. They add a lot of circulation to the cooling system.

 

these cars are made to run hot, they have a reverse cooling system , the heads are cooled first and then the block, your fan should go on at 228 degrees.

 

I don't have any numbers at the moment and haven't really been able to drive it that much in traffic since I can't haul ladders in it. I have been reading and was going to try the burping this next weekend. I did test the fans and they seem to be operating properly. I know the water pump and radiator have been replaced since i also received all the receipts with the car.

 

I was working on another problem this evening..it drains the battery.. I traced it down to the in dash cd changer pulling almost .5 amps...well i pulled the dash apart and pulled the aftermarket changer. I let it idle in the garage it did get up to 240. both fans came on as they were suppose to. I did hear a lot of gurgling after i shut it off...still planning on burpng it this weekend...

 

OK since the water pump had a lifetime warranty I went ahead and replaced it, with the thermostat (stock). as always the simplest things are the hardest to troubleshoot.....before any body ask's I am reading the forums plus i have my helms manuals....But what I am noticing is that the cooling sytems is testing better....but when i have the tester on and no way to vent I actually have to shut it down to make sure i dont blow a head gasket...and we are talking 30 to 45 minutes at 205 so i am going to pick up a new radiator cap tomorrow...does anybody els have any suggestions?

 

If you changed the water pump and did not burp it then it is sure to overheat. Also look thru the little opening on the pass side of the radiator shroud to check for debris.

 

i did the burping before and after i changed the water pump....I also looked at the debris in the condensor and ratiator...kinda devised my own little test on the suction... put a plastic walmart bag in front and it sucks it up pdq... so with the radiator cap on in 15 minutes it will be at 225 and i shut it down where as with the standt tester and no way to vent i always shut it down because of the preasure reading. usually after 35 to 45 minutes....and the temp is only at 209.....so i am going to try replacing the radiator cap...unles anybody else can give me an idea not to

 

209 was the highest temp I had befores shutting it down with the tester in place

 

letting the car idle in place its going to run hot.. its a race oriented car not something intended to run all day it your driveway.. it needs to move to run at normal temps. i don't care how many parts you throw at it its not noing to run under 220 not moving unless you tune the fans.

 

209 is not hot the fans don't come on until 230ish

 

My '87 is designed to have the primary fan come at at 228 degrees and the auxiliary fan comes on at 241 degrees. I had it checked at a corvette repair center and they said that is exactly what it should do.

 

Hey i just wanted to say thanks to every one....this is my first vette and I am having a little bit of a learnig curve plus information overlaod...My Z71 runs all day at about 210 but that it.....the vette runs great until about 220 on the open road. Once that is hit it keeps climbing so i usually shut it down...i havent had in real intraffic situations since i am working on this as well.

Thanks

 

A '95 does not require burping. There is a single brass vent screw on the thermostat housing to vent out the air while filling and during first warm up. Put a towel under it to prevent dripping on the opti-distributor.
The FSM recommends to "avoid aggressive maneuvers until at least 3 complete heat/cool cycles" after flushing and hints that the temperature will be erratic until the system has purged itself of air. The heat/cool cycles should be from 'room temp' all the way to 220+ with perhaps modest driving and back to 'room temp' again.
Do not open the system during this initial 3+ heat cycle but do shut off if the temp nears 260F (analog gauge). That's the boiling point of 50% water/antifreeze at 15psi.
I've flushed my system 3 times in the 7 years I've had my '95. Twice with no problems. The first time, the temp was all over the place and had to shut down a couple of times. Blew out some coolant warming up with the cap off.
Eventually realized the need to keep the cap on all the time and after several heat/cool cycles, the temp 'stabilized' and remained under 235F in traffic and 194F on the road (digital gauge). About 1/2 gallon was sucked up out of the overflow tank back into the cooling system during the 3 cool down cycles.
Good luck and welcome to Corvette ownership.

 

I put in a bottle of Red Line Water Wetter, which increases the ability of the coolant to absorb heat from the engine and give it up through the radiator.
http://www.redlineoil.com/Products.aspx?pcid=10

 

I thoght i had a problem with my 95 when I got it 3 weeks ago.So I shut it down and changed the coolant.Then I read the manual and found out the fan won't kick on till 227.Well it needed changed anyway.
I used the newer presone any color long life antifreeze.

I will install a lower temp fan switch soon 40 bucks.(200 deg)

 

You can install the 200 F fan switch but it won't do much to the coolant temp. Idling, the coolant temp will get to 228, the main fan will come on, the coolant will drop to about 210 F and the fan will go off and this will repeat. Turning on the fan at 200 will merely keep the fan on all the time because the radiator is not big enough to bring the coolant temp below 200 F while idling. When you get underway, the coolant temp will drop to below 200 F and the fan will go off. There isn't a thing wrong with the way the cooling system was originally designed and your vette will not be harmed by the normal temps I just posted. This is something that some new vette owners cannot get used to and they insist on installing bigger fans, different fan temp switches, etc, but they are wasting their time and money. I have been driving a stock 87 vette everyday in every kind of weather for 20 years with the stock 195 thermostat and stock fan settings with no overheating and no engine problems. By the way, GM says to shut the engine off at 260 F and let it cool down. I have never seen 260 F !
Instead of worrying and modifying the cooling sytem, save your money and effort and learn to live with how GM designed the cooling system to work. Now if you have debris stuck in the radiator and C4's suck stuff up, then clean the radiator of this debris and it will run as I described with no harm whatsoever.

 

Ok so everyone knows....when i shut it down this weekend. I was driving 70 plus on an open road. Paying attention to both the analog and digital readouts. I was returning home not more than 25 miles. the digital hit 235 and the analog was nearing the shaded area before 260 so i found a spot and shut her down PDQ.

Thanks everyone