still overheating

[Rod]

get rid of the 160 thermostat, use the cheapo mr gasket 180 works well, you can pick it up any were autozone, pepboys, Etc.

[JohnnyE]

I did notice some bubbles int the rad when I warmed it up this this morning with the rad cap off,a little bit of foaming action as the rad circulated but it did circulate well. Does that possibly mean something?

[sn75]

Any suggestions on fans? Thanks John

Look at the end of my last post

[JohnnyE]

I was kinda hoping to keep the dual set up but if the Mark Viii fan is what I need then I will get one with a 180 thermostat.

[djorgensen3]

Try cutting some trap doors into the large flat areas of the the shroud and add a hinge so that at idle the fans only pull through the areas immediately in front of them and at cruise the trap doors open and allow more air to pass through more areas of the radiator. I think your shroud with the electric setup is choking the air flow at cruise.

[JohnnyE]

It's probably a combo of choked by the shroud, shroud being to close so the effective area is cut down and wimpy fans from champion. The electric fans would even have trouble cooling at idle it would sit at 190* minimum. My belt driven fan probably sucks too as it's a flex fan with thin blades but does out perform the electrics. I am shopping around for new dual fans with new shroud design because I'm already wired for them with dual 30 amp relays.

[Ron]

JohnnyE,

Over heating in stop and go driving is usually an indication of inadequate air flow through the radiator. Over heating at highway speeds can be result from, airflow or coolant flow rate, timing, air/fuel mixture or a radiator with insufficient heat rejection rate. Any combination of these or others not mentioned could contribute to your problem.

If you would like call us at 1-800-842-5166 we maybe able to help with your cooling problem..


Ron Davis

[JohnnyE]

Update...so I flushed out the system and filled it with water to go street legals this weekend and I started noticing the water had bubble in it while running with the cap off and it kept pouring out the fill cap. It would get a white bubble film on the surface so I poured more water in to the cap to clear the bubbles but they kept coming. Drove the car around for a few hours and tried it again in the morning took the cap off and warmed her up, as soon as the thermostat opened the bubble came and the the froth on the top. I now suspect blown head gasket, warped head, or a crack. I have no white smoke or water in my oil. I guess I should do more testing to confirm but the bubbles in the rad and the overheating are good indicators. Time to consider a new block and heads anyway. Thanks for the tips I would have never checked the rad for bubbles.

[TT302Z28]

Go to Napa and get the test kit, it really is the best way to know for sure.

[Ron]

If I understood from the beginning, the heating problem was at stoplights, at hi-way speeds, no problem. The radiator and fan system were changed and so did the problem. As I understand it now. The car runs cool sitting still and hot driving down the road. Unless you have overheated the motor and hurt it I would not think the block and heads would be at fault, to be sure though a combustion check wouldn’t hurt. If you want to fix the problem you originally had, put the stock radiator back in and get a good (GM) fan clutch, factory fan and shroud on it. The original radiator evidently worked fine when the motor was making power pushing the car down the road, so we know it works. At Idle the motor is making just enough power to keep itself running…maybe 15hp? The radiator demonstrated it could easily cool that much power it just needed more air. So putting quality parts in the fan system like fan, clutch and shroud should take care of the problem.

Ron Davis

[DJenkins]

I run a similar setup on my BB and get had some heating when sitting in traffic. It turned out to be a thermostat that was not fully opening all the way.

[SparkyRnD]

if you have air bubbles, then you have air coming into the system, which can be a leaking head gasket pressurizing the coolant system. It would be worth a check to see what your compression is on the cylinders to see if there is a leak somewhere.

[JohnnyE]

Thanks to everyone that took the time to reply to my post. I decided put in some Spal 30102130 fans and they keep it cool now in the city and the highway 150 - 160 in town and 180 - 190 on the highway. The hypertech 4026 fan switch doesn't seem to work though the fans come on around 200-220 and then just stay on all the time. I am going to change up for a 180 stat and a different fan switch this winter.

[anthonys 69]

I see you have a new water pump. I don’t know if this will help but it worth mentioning. Iv seen people put new corvette water pumps on there cars because if it good for a corvette its got to be good for my car right. Corvettes run a reverse flow water pump for serpentine belt and your running a v belt the pulley would fit. And the impeller will be turning the wrong way cause cavitations and making bubbles. The block test is a great idea. You also can check for possible head gasket failure by pressure testing your cooling system over night and see if the car has a misfire and runs rough until it burns of the water. Good luck

[anthonys 69]

Just trying to help, we had a firebird in the shop and it was getting hot at long lights. Found out that some of the trim from around and under the radiator was missing allowing the hot engine air from the radiator to re-circulate around and keep passing through the radiator the radiator wouldn’t cool down until the got moving