OK, here's one for you guys. Current 4 core brass/copper radiator in a 1985 GMC 1 ton tilt rollback with 455 Stage 1 standard bore. As long as I'm moving, not too many issues. Once I stop, temps climb to over 230. Quickly. Would I be better off repairing the current radiator (it is has a small leak) or going to aluminum and what size?
Brad, That sounds like an air flow problem or an ignition timing issue. Do you have a good shroud with the fan placed properly inside of it? What is the ignition timing at idle? Are you using vacuum advance and is it on ported or manifold vacuum? What is the timing at cruise RPM.
fix the leak...put a heavy duty fan clutch on it and a new 15lb cap...../ unless your on electric fan
Has shroud, timed per you Larry, vacuum advance, I'd have to check the mark on the balancer to see cruise timing. Zero issues until I stop then climbs quickly. Heavy duty clutch, etc. If I pop the hood, temps drop and stabilize at thermostat rating. I'm thinking flow issue. Just wondering if a less restrictive radiator (id: 2 core aluminum) would be better.
See what the timing is when it is idling Brad. If it is low single digits, it will want to heat up. Also check that the vacuum advance is actually working.
New water pump, thermostat, hoses belts, etc. radiator back flushed and clean. Radiator has a small leak that’s just weeping a little (started just after the back flush). Would a 2 core aluminum with 1.25” tubes cool that 455 or would I be better off repairing the copper and brass 4 core that I know is somewhat restrictive? I’ve always had this issue since we put the combo together, I would just pop the hood. Just looking for ideas now that the radiator is 25 years old and starting to fail. What would you do?
where is your temp sensor location that your getting that reading .. ....a 2 core aluminum with 1.25” tubes would do you justice over a 25 year old radiator
Absolutely. That would be the ultimate. A 25 year old brass/copper radiator is almost certainly partially blocked with solder bloom. You can't flush that out.
Stock location for temp sensor. It’s done this for a long time, like I said since we put it together really, over 25 years ago. I believe the old radiator is just, well, old. When I do it, I’m doing the heater core too. Everything else is fresh in November 2018 for the MCACN trip.
Also, the total number of tubes counts (pun lol). Vertical tube spacing (and correspondingly fin heigth) will determine how many total tubes can be stacked in a particular core. A radiator with only 3 tubes will not outcool a radiator with 300 tubes (okay extreme examples but you get the point) no matter how thick the tubes
I should have followed up on this a long time ago. Went with Aluminum 2 core with the 1.25" tubes. I can now idle all day, hood down and it barely reaches thermostat rating. Much more air flow through the radiator and that seems to have solved the issue.
