[C2] 327 glide, 220* @ 65 mph - 180* in traffic.
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,651
Likes: 408
From: Australia
327 glide, 220* @ 65 mph - 180* in traffic.
67 - 327 - 300 PG with AC and 336 rear.
Unknown miles on engine, but Im “guessing” been rebuilt at some time in its life.
On a 70* day, AC off, cruising @ 65 - 70 on the freeway, RPM around 2500, temp gage gets to 220+ after about 10 minutes, but it cools back down to 180 - 190* after around 10 minutes and stay all day, if I’m in local traffic.
Checked with IR gun.
Timing is good (as per Lars papers)
BTW It did this before I recurved the dist. and swapped the thermostat out for a new 160*
New aluminium radiator (unknown brand) and coolant flows back to the surge tank when the thermostat opens, but how much, I don’t know.
So it would seem I have a coolant flow problem, not an air flow problem, even though there’s a trans cooler and condenser in front of the radiator.
It doesn’t puke coolant out, although I’ve only been up at that speed and temp for maybe 20 minutes and it takes half that time to come down again.
Hoses good, spring present and not collapsing.
Long post, sorry, just wanted to cover everything.
Should I even be concerned ?
Thanks for any advice, it’s a new one to me.
Unknown miles on engine, but Im “guessing” been rebuilt at some time in its life.
On a 70* day, AC off, cruising @ 65 - 70 on the freeway, RPM around 2500, temp gage gets to 220+ after about 10 minutes, but it cools back down to 180 - 190* after around 10 minutes and stay all day, if I’m in local traffic.
Checked with IR gun.
Timing is good (as per Lars papers)
BTW It did this before I recurved the dist. and swapped the thermostat out for a new 160*
New aluminium radiator (unknown brand) and coolant flows back to the surge tank when the thermostat opens, but how much, I don’t know.
So it would seem I have a coolant flow problem, not an air flow problem, even though there’s a trans cooler and condenser in front of the radiator.
It doesn’t puke coolant out, although I’ve only been up at that speed and temp for maybe 20 minutes and it takes half that time to come down again.
Hoses good, spring present and not collapsing.
Long post, sorry, just wanted to cover everything.
Should I even be concerned ?
Thanks for any advice, it’s a new one to me.
Racer
Joined: Dec 2025
Posts: 352
Likes: 132
From: Pachuta, MS
If it'll stay cool in traffic then that tends to rule out the fan clutch. Since your problem is at highway speeds, one thing that occurs to me is a worn/damaged water pump impeller that cavitates at speed. The other thing that occurs to me is that the transmission may be overheating. I question the need for the add-on cooler and wonder if that was an attempt to fix a transmission problem but if I were forced to guess at your problem given your symptoms, I would say trapped air and your system needs to be burped. Of course, this could simply be a C2 being a C2 but that initial temperature spike would trouble me. I would also look for ways for air flow to go around the radiator at speed but through the radiator and fan at low speeds.
Last edited by acstephenson; Today at 02:35 AM.
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,651
Likes: 408
From: Australia
Sorry, I should have been clearer about the trans cooler, it’s factory and sits right in the middle, behind the grill.
I’ve run it up to temp without the cap on the surge tank, so thought that would eliminate any trapped air.
There are a lot of gaps around the shroud that could be sealed better, perhaps that’ll help, but I’m also thinking, maybe the water pump impeller has rotted away.
I can see the flow of coolant back to the surge tank, so it’s working, but how well, is the question ?
I’ve run it up to temp without the cap on the surge tank, so thought that would eliminate any trapped air.
There are a lot of gaps around the shroud that could be sealed better, perhaps that’ll help, but I’m also thinking, maybe the water pump impeller has rotted away.
I can see the flow of coolant back to the surge tank, so it’s working, but how well, is the question ?
