95maroboi

So after 2 long years of waiting for my engine to be rebuilt, I finally got the car back and it won't stop over heating.the tempature slowly keeps climbing up the red line wiether it's idling or driving. I verified the tempature with a scanner to make sure it wasn't a bad sensor.the only changes to the cooling system was going from a mechanical pump to a brand new electric water pump and a new pair of electric fans because the stock ones wouldn't fit my cog set up for my supercharger . I've bleed the system completely .no air bubbles or hissing coming from the bleeder screws when opened at 180+ degrees. Also changed the thermostat and put it in boiling water to make sure it's opening and closing properly . Both fans are kicking on also.Any advice that might help would be great. Thanks !

Injuneer

Are the fans rotating in the correct direction?

Probably need a bit more description of the engine.

TA Dreaming

Is coolant actually flowing ie your EWP is working? Overheating at idle tells me it's a very obvious issue as the engine should be able to remain cool even with minimal air flow from the fans through the radiator.

Positive the correct head gaskets were used?

gaedbo

With the radiator cap off, can you see flow taking place in the radiator ?

Are the upper and lower radiator hoses hot or cold ?

Are you able to verify the water pump is actually running, and is it possible it is running in the wrong direction ? (Maybe it can't, I don't know....just throwing that out there)

95maroboi

Yes the fans are pulling . They are 12 inch Hayden 650 cfm fans.im thinking I need better fans. I'm also running the stock radiator .The engine went from 355 cu in with v1 si trim and now is a 385 cu inch lt1 with a cogged v7 ys super charger.

95maroboi

I hope the rite gaskets were used. It was rebuilt at a machine shop so I hope they know what they were doing. The water pump is defiantly flowing really good. I cant open the radiator without coolant flowing out because of how fast it pushes it.if I shut the engine off and run just the water pump the engine tempature starts dropping down.

95maroboi

Yes the hoses are hot.theres no bubbles or hissing when I open the bleeder screws when the thermostat opens so I know there's no air in the system.im thinking my stock radiator and 2 12 inch 850 cfm fans can't keep the stroker motor cooled

Injuneer

If turning the fans off reduces the problem, there is definitely a problem with the fans. Is there any possibility the intercooler (if it's air-to-air) hot air is flowing into the front of the radiator? Although that would appear to be a problem at idle.

Although we both had aftermarket aluminum radiators, a buddy making 1,125HP with a Vortech S/C 383 was running stock fans. I am also running stock fans with a 300-shot of nitrous. Never a problem with cooling. On the other hand, we were both using the stock water pump. The shop that built both engines refused to install electric water pumps on engines like this.

Do you have any block filler?

How did you power the electric water pump? Any connections to the fan relays?

95maroboi

I'm using the vortech after cooler so it's a air to water.i would love to use my stock fans again but they won't fit with my cog set up. The 355 motor I had befor the rebuild never over heated with the stock radiator and stock fans so that's why I'm also thinking the fans I'm using now arnt up to par .there is no block fillers in the block. Im not sure how there powering the water pump because the shop who built it hooked all that up. I wonder why the shop that built your engines don't like electric water pumps? I hope that's not my problem

Injuneer

If you have the overheating at idle it's not likely because you used an electric water pump. At least as long as it is operating properly. Shop didn't feel the fixed flow rate was adequate for high heat load, high RPM operation when you want increased flow. They also would not use block fill. They showed me a B-Body LT1 that constantly overheated because of the block fill. I've seen others claim they have no problems with the electric pumps in high HP, high RPM applications.

I mentioned the fan relays because I remember a post on a Corvette forum where the guy said he used the low speed relay for the water pump, and when the 3-relay system switched to high speed, it shut the water pump off. Again, just trying to think of things off the wall, because the problem is very unusual.

Is there a shroud on the rear of the radiator around the fans? Is the stock radiator sealed completely to the bulkhead, to prevent bypass? Is the front baffle leading up from the air dam still in place?

95maroboi

The fans don't have a shroud. There 2.5 inches thick and almost touch the pulley on the super charger.ive been seeing other people some how using the stock fans on with a cog set up so I'm gonna try to make it work.there is no block filler in the motor. The air dam is still in place.i hooked up a Portable fan under neath the car to force air into the radiator and the car would still over heat but take twice as long to do so without the using the fan.the coolant level stays to the completely full so I know there's no leaks of any kind.

TGGodfrey

What your going to need to do at this point is to get a temp reading on the coolant as it enters the radiator and as it exits to see if your radiator is reducing the coolant temp.

do you have a fluke or another type of meter that has an electronic thermocouple?

Something like this would work, you need to be able to get a reading of both inlet and outlet at the same time.

Take your hose off and clamp the thermocouple into the hose. This will leak a little during testing but your not too concerned about that as long as the hose clamps are tight and hoses are not blowing off.

Compare your incoming temp on the radiator to your outgoing temps..... Obviously if the coolant entering the motor is not cool, then the radiator and/or fans are not able to keep up. There is also the possability that the water pump is pushing coolant through the radiator too fast and not allowing the radiator a chance to dissipate heat. An Aluminum radiator might be required. This test will at least put you on the right track as far as what is causing the temps to keep increasing.

Like mentioned before, verify the pump is still running when your fans kick on from low to hi. You can do this without running the car, just jumper the relays on low, verify water pump is getting power, jumper the fans to hi and recheck the pump feed.

Here is a shot in the dark.....I didnt see where you mentioned any type of ECU tuning. Did anyone retune the timing maps in your ECU and perhaps maybe they advanced them too far causing this? Pull your plugs and read them for timing.

Chimera96

OP

your after market fans...are they the correct orientation (push or pull) fans mounted to work in the direction you have mounted them?

your T stat "could" be sticking....

Chimera96

assume you have confirmed the EWP is wired so it rotates correctly (reverse flow LT1)

95maroboi

Yes the fans are pulling . I replaced the old thermostat with a new one and out it into boiling water to verfiy it's opening at 180