The Stovebolt Site Forums The Shop Area The HiPo Shop Do you think I need a new water pump? UPDATE

I'm running the stock radiator in my 49 AD with a SBC. Had the radiator gone through and cleaned up. Thermostat is working. Flex-a-lite fan with shroud.
If the truck is running at idle the water temp seems to stabilize at about 190 but if I bring the RPMs up to 1750-2000 or am driving, the temp keeps climbing to 250 or I shut it down.
Seems like it is getting some flow but not enough?
Should I go with one of the hi flow (30-40% more) pumps?

With the advice received here I went on ebay and bought a Champion 3 row aluminum radiator. Problem solved!

if you're getting overheating when moving and not when standing still, the problem isn't the water pump
which small block? mechanical or elec gauge? stock non-pressure rad cap? when it gets to 250 does it puke all the water out?

Bill

The drive line is out of a 74 Camaro. 350 with mid level cam and intake.
Gauges are new Omega elect. Pressure cap and puke tank. When I release pressure on the cap it pukes.
Should I try it w/o the thermostat and see if that makes a diff?

190/195 thermostat? might try a 180, but usually no stat at all makes for hotter - what rating pressure cap? a 14# [probably what the Camaro had] might take 250* but I don't think an original rad would stand that for long, and I'd expect a 7# to blow off itself by 250* .... have you used a laser thermometer to check the actual temp compared to the gauge? I'd suspect a gauge problem or electric fan impeding air flow

Bill

Timing and compression are good????

It's a new 180 thermostat, new 16lb cap,new 16in Flexalite with shroud I think it was rated at 2500cfm but don't have that number handy. The fan kicks in at about 190 so that's why it stabilizes there at idle but as soon as I rev it up or take it out on the road the temp starts climbing and it's only been in the 60's. This aint going to work during the summer!
No mechanical fan. It wouldn't clear the bottom hose of the rad.

Timed it with a light but I can check again. Comp is good, I went through the motor when I pulled it from the Camaro about 20 years ago and rechecked everything as I was building the truck during the last 2 years.

Just a thought but would the anti freeze/water ratio do this? It probably has about 2 gal of antifreeze in it and holds 3 gallons total.
Maybe it needs some 40 Below or something like that?

Anti freeze won't carry off as much heat as water in the chemistry lab, but I have not seen that much difference in practice. If the temps go up and never stabilize, I really don't think I would spend much time going down that bunny hole.

Do you know if your fan is turning on and off per the switch settings (assuming it is switched on and off with a thermistor switch and relay)??

It should cool better when moving than sitting still, unless the fan and shroud block airflow when moving, and the fan is not coming on. If that makes sense.

Have you bled the system to make sure you don't have an air pocket that is preventing the water pump from moving water through the motor? I would guess your radiator cap is the highest point of the cooling system, take it off and while the motor is running, fill it full, let it run, fill it full, squeeze the top radiator hose and make sure you feel water running through it and that it gets hot....

Yes the fan is turning on and off at 190.
Haven't tried to bleed the system but I have filled it and let it run and checked to see if it went down (it doesn't).
It appears I am getting circulation because when it is started cold the top tank remains cool until the temp gauge gets up to 180 then the top hose and tank get warm in a hurry.
I do have a trans cooler and A/C condenser in front of the radiator. They are both new from Old Air and I can't see them causing this because it doesn't overheat at idle with the fan going, only when revved up or driven And when the fan is running there is lots of air moving thru the rad. The fan is 2500cfm and I have a shroud.
Maybe I'll change the timing. Should I advance or retard to help the cooling?
Thanks for all of your replies. I know with the Stovebolt brain trust we can figure this out.

I think you may be expecting too much from the original rad - for starters it wasn't designed to hold any pressure at all, or 3# at most, with a 16# cap at 250 it's likely to be getting close to 16# ... the trans cooler and condenser will not only be blocking air flow, but adding a lot of heat to that air, the trans will get as hot as the engine pretty quick - and positioning of those as well as of the fan will change things

again, spot check actual temperatures everywhere with a digital thermometer

Bill

I went the same route as you with the stock radiator in my 46 including getting it recored twice and it just ran hot. I did put in a high volume pump and 2700 cfm electric fan. All i did with the higher pressure cap was cause the seams to leak. Finally replaced the radiator with a Autorad aluminum radiator and problem solved. I also put in the Centech electric fan control switch. Runs about 190 deg on the hottest days.

Mike

Thanks for the info guys. Looks like one of these
http://www.championradiators.com/product/AE5100
is in my future.

To answer your question about timing retard to decrease the heat in the engine. Within reason.

x2

especially with an agressive cam.

Be careful with the cheaper aluminum radiators. They cut the cost by using thinner materials. Try to stay with one of the major brands. You might give a call and talk to the guys at Hot Rod Express about what they carry. Very good to talk to. Good luck.

Mike