My first question on here and I could use some help. Also, I did some searching for this issue but didn't really find much.

I bought my car on Sunday and drove it 125 miles home, mostly on the highway. The car has 88k miles and had been sitting a lot for the last 5 years according to the last owner. Got it home, parked it in the garage, and thought everything was great. Drove it around the neighborhood last night taking the wife and kids for their first rides and when I went to park the car in the garage the temperature went up above 200. After I shut it off I heard it making a bubbling sound in what I believe was in the reservoir, not the radiator. There was also steam coming out of the defroster vent, enough to fog up the windshield near the vent. I popped the hood, put a fan on the engine, and the bubbling sound/fog stopped within a couple minutes.

So, I took the car out again tonight to try and figure it out, really watching the temperature. At speeds of 40ish and up everything looked what I assume to be fine, around 170. I drove about 5 miles and stopped at AutoZone for a few minutes to get fuses. When I came back out the thermometer read 195 and went to 200 as I pulled out of the lot. Got back up to speed and the temp quickly came back down to about 175. Got back in the neighborhood and the temp went up to 200+ as I was on the local streets and parking it in the garage. The fog also came back but I put the fan on it immediately and I didn't hear the bubbling.

Obviously there's something going on with the coolant system but I'm not sure where to start. I checked the coolant level in the overflow when the car cooled down and it looked fine. Thinking back on it now my wife said she had a couple of drops of water on her feet yesterday, most likely from the heater core. I think that's everything I know for now. Any suggestions would be much appreciated!

 

Might be the heater core or just the drain tubes pluged up smell it and see

 

Your heater core needs to be replaced. Fun job. To verify that the heater core is the problem, remove the passenger side kick panel (a couple of 7mm screws). If the heater core is leaking it will leave a rusty stain on the foam rubber. I saw a nice picture of this recently but unfortunately I forgot to download it.

Here's a description of how to do it with a plethora (I always wanted to use that word) of pictures:

https://www.corvetteforum.com/forums...post1569252027

NORMAL coolant temperatures for your car are in the 210° to 220° range. Don't get concerned unless it goes over 250°. Up to 250° can happen without hurting anything.

 

Is there a sarcasm emoticon? (Always wanted to use that word!)

 

Great, I was afraid that was the problem. I've done a similar replacement before in a Chevy Beretta and it required taking out the dash. That project sucked.

So, here's my next novice question because I've never had to replace one on any car I've ever owned. Can I still drive the car at all or am I risking really messing something up? I don't want to take the chance on screwing it up more by just starting it to move around the garage or even driving it to the shop if I decide to have it replaced instead of doing the change myself.

One last question, where is a good place to get a replacement core? Is it the kind of the part I can get at AutoZone or do I need to go to a Corvette specific place? Basically I don't want to do this job more than once if I can help it. Thanks for all the info.

 

If it is the heater core leaking, you should be able to temporarily disconnect the two heater hoses and connect them together effectively having the coolant not going into the heater core.

Try Rockauto.com for a heater core. Also check out NAPA and CarQuest. I would stay away from the chain parts stores like AutoZone, O'Reilly's and such.

This would also be a good time to check the upper and lower radiator hoses for any signs of cracking or drying out. You will have to drain some coolant anyway so do a complete cooling system flush and refill using a good ethlyene glycol (green) coolant and distilled water in a 50-50 mix.

 

When draining the coolant pull out both knock sensores for a proper flush and safety for the opti. Use the proper tourqe and dope I just put in new ones. Could not bring myself to put back 20 year old parts

 

Welcome to the Forum and the insanity of Corvette owners.

Like noted above, steam coming out and steaming up the windshield probably the heater core.

Be aware that these cars run HOT. The fan does not come on until the temp goes up to 228. So the temperatures you were seeing are not something to worry about. I am old school and get nervous with temps in the 230+ range. So I installed a 160 thermostat and had the fan turn on point re-programed in the computer so it runs cooler. If your the same way and don't have someone to change the computer, then get a Flow-Kool water pump. It will drop your temp 10-15 degrees.

 

I would disconnect the heater core lines and mate them together for the time being. Its likely that the coolant needs to be drained and replaced as well. Might as well do as many hoses as possible since its been sitting, and especially the brake fluid.

Otherwise your temperatures are behaving normally I think.

 

with Vader86 on other hoses. Note the hoses should have date stamped on them. Consider TB bypass when you change them out.

 

Thanks all. I'm going to get the connector part to bypass the core tonight. Got a quote from my mechanic of $600 for him to replace the core (mostly labor) so I'll do the project myself sometime this winter. Good to know about the normal operating range too. I appreciate all the info and tips!

 

I bypassed the core tonight and it seemed to fix the issues. Guess I'll plan on doing the heater core sometime this winter when the weather turns crappy.