vettef6

I am having problems with my water temperature. Even though I am using a Meziere water pump my temperature goes up to over 220° at about 70mph. At idle the temp. is about 200°; but the faster I drive the hotter the engine gets. When I had my 350ci with about 400HP installed I had no problems at all (190° at all times). Just swapping engines 350ci vs 396ci with about 500HP made the temperature rise like crazy. As most of you know, we have a lot of roads without speed limits and I can’t drive any faster than about 70mph.

Does anyone know what can be done to solve my problem?

85vet

Install a BeCool radiator.

Had similar problem when current 383 buildup was completed.

More cubes = more heat

Just a note - I have a tranny cooler in front and oil cooler behind the radiaitor and it still keeps the engine cool.

RonRed89

I went with a DeWitts C4 radiator and dropped the temps by atleast 20 degrees. On a humid and hot day, the water temp doesn't go above 200 in traffic or 190 on the highway. When its cooler, 17x is the norm.

Tom DeWitt is a great guy to deal with and is also a forum sponsor. The fit of the DeWitts unit is very good.

Ron

Nathan Plemons

Have you double checked your thermostat for proper function? At normal cruise your 396 shouldn't run a lot hotter than a 350.

tjwong

I am using a stock radiator in my 396 LT4 and I am even running a blower. Did you make sure there wasn't any trapped air in the system. Did you bleed it with the bleeder screw on top of the thermostat? Also as the others were saying check the stat for being stuck. I run a 160 degree stat.

vader86

I would check up on the thermostat function first, though I would keep it as 180 if you do ever drive the car in german winters.

If its working fine, the only thing I can think of is that your radiator is just not adequate to the task, and you should get a BeCool/Griffin/Davis one.

MaddMaxx

I am running the stock cooling system on my 396 LT4. The only changes have been the TB bypass and 160 Stat. I have the fans set at 185, and the temp never goes above 190 even when it is 95 degrees here in Florida and I am in heavy traffic. Something seems odd, as my car even when stock would run much cooler at highway speeds.

How is the oil temp?

Bluewasp

Where do you live in Germany?

dwestsr

Have you considered that the flow capability of the Meziere electric pump is half that of the OE mechanical pump? The electric pump is designed for racing to reduce hp loss. Since the electric pump flow does not vary with engine speed, it stands to reason that , in a marginal cooling situation, the faster you go , the hotter it will run. In lieu of a larger radiator, you might want to try a mechanical water pump

RichS

Stock radiator here as well and no problems. Runs around 180. Maybe 200 after a good beating.

vettef6

Thanks for the quick replies; you fellows sure have a lot of questions. Let’s see if I can answer them.

I have both, a 160° and a 180° thermostat, the temp. stays the same. The fans are set to 185°-190°. There should be enough air going through the radiator at high speeds; normally you won’t have to have the fans on.

I bypassed the TB and did bleed the system using the bleeder screw on top of the thermostat.

Just drive my Vette on non rainy days from about the end of March until November.

My oil temp. using an oil cooler is about the same as the water temp; no problem with the oil temp.

Would hate to switch back to a stock water pump (labor and parts); I switched to an electric water pump not only because of the HP gain, but because I thought it would be better than stock. Never heard of anyone having problems with the amount of flow because of an elec. pump.

I tried switching the wires that go to the pump (changing rotating direction) didn’t help either.

BTW, I live near Braunschweig about 330km north of Frankfurt.

Thanks
Arnold

red L98

how many GPM is that water pump ? i dont have an LT1 but the pump i have flows 70 GPM . most pumps only flow 37 GPM that could be ur problem.

vettef6

I just looked it up and Meziere states the normal pump flows 35GPM vs 55GPM for the heavy duty. I have the normal 35GPM pump.

Do you really think the stock pump flows 70GPM?

dwestsr

My point is: that the electric pump flow is constant. Whereas the flow may be sufficient @ low speed, It may not be at high vehicle speeds. If the max flow is equal to the mechanical pump , there is no problem. If not, It could explain the higher temps at speed.

vettef6

David,
I know what you mean. I really do feel as if it were the pump but other people are also running this pump and with even more HP.

vettef6

Does anyone know how high the flow#'s are from the stock LT1 water pump?

BrianCunningham

Can't comment on a 396 with a stock radiator, but I've got the HD waterpump and a racing radiator with the stock engine, and it's great. I've heard people have problems with substained high rpm's with the stock pumps due to cavitation.

Another problem could be head gaskets, either they were put on upsidedown, or non reverse flow gaskets were used. I know of a SpeedGT team car that keep overheating at speed, because the engine builder was using the wrong gaskets!

Z06_BluByU

I have a 383, with the fans comming on around 182-185* and have no problems.. on a hot, humid florida day in bumper to bumper traffic at a stand still with the A/C on Max I may see 219*