[chiphead]

My fresh '67 400 has 1000 miles on it. 9.3:1, 93 octane gas. 34* of timing by 3000 RPM. Q-jet has 73 jets and 41 rods. APT open 2.5 turns. No thermostat, 4-core desert cooler radiator (bought used). HD thermo clutch, 19" fan. 8 bolt pump and cover in good shape. Divider tweaked. No fan shroud. Have had radiator rodded out. '67 LeMans with 3.55s and A/T w/stall converter. Huge tranny cooler.

It runs 200 degrees all the time, all year. 30 degrees or 90 degrees outside, it runs 205 max. Idling or going down road. What gives???

[speedshopmike]

temp gauge broken?
put in a thermostat.

[speedshopmike]

install fan shroud

[kate`s67gto]

As Mike said add a fan shroud and verify the temp guage. If your running with no thermostat and have temps of 205 @90* idling or running down a road, i don`t see a problem? Your not running too hot....

[Geoff]

I recently switched from a downflow to a crossflow radiator. I was not able to use my original shroud, as it interfered with the new hose locations. Even though the core dimensions of both radiators were the same, the engine ran noticably hotter with the new radiator. All that was different was the shroud was missing. Hmmm??
I made a new shroud from alum & presto! the hot-running was cured. I was surprised by how much the shroud lowered the temp.
You should also ditch the clutch fan & use the Flex A lite 19", 6 blade, blue centre, stainless steel blade flex fan. A clutch fan slips & loses speed & therefore loses airflow. A flex fan doesn't slip, period. This fan is noisy, but it cools.
And you are using vac adv hooked to a manifold source, right?

[chiphead]

You got me on that one.. The MSD Billet dist I have doesnt have a vac advance. Guess I need to score one one day.

Which PY fan shroud do I need for a '67 LeMans? Its AT, has the bigger factory size radiator, AC car with AC removed.

The only other thing I can think of is rust/scale in the radiator. My 350 dumped crap into the rad. So I had it rodded out. But I'm wondering if the shop did a crappy job, or if any scale from the new 400 got wedged in there? How do you check a radiator for flow w/o having it rodded again? There arent any cold spots on radiator, and it seems to flow. But some brown gook keeps washing up in the rad. Heads were pressure tested, and the motor seems healthy enough. 1 gallon of antifreeze to the rest water.

[Geoff]

MY 66 GTO is also A/C like yours, came with the tall 19" radiator. Uses the 19+" fan.
If you have/had an engine that dumps crap into the radiator & blocks the tubes, then you should use a filter in the top hose; it collects the junk before it blocks the radiator. I had to use one on a Mopar I had. It was a marine engine that had salt water in it & it kept producing junk that blocked the radiator core. Every 2 weeks, I had to clean out the filter because it would become blocked & then cause overheating. Finally after many months, no more junk & I took the filter off!!
To check your radiator core, drain the water & use a torch to look down through the radiator cap hole. If you can see some tubes blocked by debri, it needs to be rodded. Another test is to remove the radiator, block both hose outlets & fill it with water through the radiator cap hole. Then remove the plug from the bottom opening & watch how quickly the water drains. If it is very slow, & takes forever for the last trickle to stop, it is blocked. If it drains fairly quickly, it is probably ok.

[chiphead]

Thanks..

What's the best way to flush the engine's water passages? I'm going to flush the system and install a Be-Cool 160* high flow, fail-safe stat.

chip