Need advice on cooling my '88 in heavy traffic...

[Alan G.]

Hi all.

I have a 1988 35th Anniversary Edition Corvette (#525). It is in great mechanical condition, but like any Corvette, it hates heavy traffic and slow speeds!

I live in the Washington D.C. area (traffic is terrible here). When I drive home around 5 PM in the summer, my Vette often reaches temps exceeding 220 degrees.

My Vette has the stock oil cooler, and I've added a transmission fluid cooler...are there any other measures I can take to help her run cooler? Like I said, it is very well maintained...

I'm thinking there has got to be auxiliary oil coolers, more powerful fans for the radiator, or some type of air-induction system that could help her get "more air" to the radiator...

Any helpful replies will be appreciated.

Also, if any of you live in the D.C. / Northern VA area and know of any Corvette Clubs out here, please let me know.

Thanks!

Al

[Jerry Clark]

Re: Need advice on cooling my '88 in heavy traffic

Hello Alan:

I'm no C4 expert by any stretch of anyones imagination but I'll give this one a crack, If I remember correctly your particular generation of Corvette engine is designed to run hot,and 220 would not be uncommon, I guess it depends on how much hotter than 220 yours becomes. Do you see any evidence of coolant loss when hot or parking after a hotter than normal drive ?

jerry

[Robert C.]

Re: Need advice on cooling my '88 in heavy traffic

C-5s are made to run hot! 220 d. is not all that hot. Your aux. electric fan can be set to come on at a lower temp. Their are other aftermarket fans available that cool a whole lot better than the stock one. Look in the Mid-America Design Corvette catalog for many add-on cooling parts.You can get them on the web, call their 800 # and they will send you a catalog.

[Alan G.]

Re: Need advice on cooling my '88 in heavy traffic

Hi Jerry...

No...my coolant is always full/always "clean and green"...my mechanic said the same thing...that it is normal. I guess I've gotten used to seeing it in the 170 degree area at cruising speed, and get a bit concerned when it approaches 220.

Thanks for the reply :-)

Al

[Alan G.]

Re: Need advice on cooling my '88 in heavy traffic

Thanks for the reply! :-)

I'll check into the fans...also, I've noticed Mid America sells exhaust tape...it supposedly lessens the amount of heat from the pipes into your engine compartment...I'm considering adding the tape when I install my new exhaust (stainless steel, cat-back) soon.

Thanks again,

Al

[Jerry Clark]

Re: Need advice on cooling my '88 in heavy traffic

Hi Alan:

As long as you are experiencing none of the normal symptoms of a engine that has overheated sit back and enjoy the ride. That is one of my favorite C4s bested only by the 96 Gran Sport convertible, with 6 spd, of course.

jerry

[Bill D.]

Re: Need advice on cooling my '88 in heavy traffic

Alan, your 88 is designed to cycle between 195 and 229 degrees.The warmer temp promotes fuel atomization and mixing for a cleaner and more complete combustion to lower emissions.As others have told you,a low temp fan switch is available that will turn the fans on sooner to keep the high side lower. The down side is a slight increase in emissions and fuel consumption.Another way to turn the fans on is to turn on the air conditioning.When the a/c is on the fans are turned on no matter what the coolant temp is.Bottom line, drive and enjoy it sounds fine! WB

[Martin M.]

Re: Need advice on cooling my '88 in heavy traffic

Probably not a good idea to tape your exhaust. Almost all header mfg's state that doing this will void the warranty. Street rodders keep a lot of heat out of the engine compartment by adding exhaust shields above the exhaust manifolds. Did it on my '32 rdstr and it dropped the water temp 5 degrees, and stopped the vaper lock

Marty

[Alan G.]

Re: Need advice on cooling my '88 in heavy traffic

Thanks Marty!

I was wondering about that exhaust tape...seems that after time, it would deteriorate and unravel...

Thanks for the tips about the exhaust shields!

Al

[Alan G.]

Re: Need advice on cooling my '88 in heavy traffic

Wow! Thanks!

I had no idea about turning on the AC...heck, when it went over 220, I'd open the windows and turn on the heater (would drop it 20 degrees easy).

I'm not much of a mechanic, so your tips help greatly...looks like I have nothing to worry about.

Thanks again :-)

Al

[Fred Oliva]

Re: Need advice on cooling my '88 in heavy traffic

Alan,

C4's are designed to run at these temperatures for emissions purposes. Also, be aware that higher temperatures tend to make the engine to run more efficiently & give less cylinder bore wear.

In reality, certain C4 engines tend to make more HP at lower temperatures, probably due to a colder, denser, air charge entering the engine. This is the case on my '93 LT1. I once ran a 13.3 @105MPH 1/4 mile on a cold night with the engine temp at 112 deg F.

Someone stated that the higher temperatues promoted better fuel atomization. I believe that this was true for a carburated engine that uses a 'wet' intake manifold, but not for a port injected engine that uses a 'dry' manifold. Fuel atomization on a port injection engine is a function of the injector design & fuel pressure.

So, you have to ask yourself WHY you want the engine to run at a lower temperature. If you're in persuit of more power, there are several things you can do. Installing a lower thermostat will reduce the lowest limit that the engine CAN run at, however, now you need to make some cooling system changes in order to MAKE the engine run at a lower temperature. On my car, I've got a reprogrammed chip to turn on the fans at a lower temp. You can also rewire the fan relays so they're on all the time. Several of the larger aftermarket suppliers make kits to do this. The kit wires the relays to an override switch so you can turn the fans at will.

As far as your headers go, I'd recommend a thermal barrier coating like Jet-Hot. This coating is applied to the inside as well as outside of the header. In my case, I had this done to the stock manifolds. As someone mentioned, heat shields will also help.

I also use a product called 'Water Wetter' in the cooling system. This reduces the formation of steam bubbles in the coolant around the cylinder bores by lowering the surface tension of the coolant. Thus, the bubbles collapse in on themselves. This change alone lowered my operating temps by 2 or 3 degrees.

With all these changes, my '93 dosen't run above 180 deg in traffic on a hot Florida day, and under 190 after back to back autocross runs with a 10 min wait on the grid inbetween.

Hope this helps.

Fred O

[Jerry Clark]

Re: Need advice on cooling my '88 in heavy traffic

Hello Fred:

I was always under the impression that cooler fuel had better combustion properties, why did we use "cool cans" at the drags ?

jerry

[Fred Oliva]

Re: Need advice on cooling my '88 in heavy traffic

Jerry,

Good question. I think the theory is that the cold fuel leads to a cold air-fuel charge. Since colder charges are more dense, you can get more charge packed into the cylinder.

However, in carbureted systems with a wet intake manifold (where the manifold ports fuel-air & not just air), the fuel-air charge enters the manifold, makes some turns, and collides with the walls of the plemum & ports. This causes some of the fuel to drop out out of suspension & puddle on the bottom of the manifold. This causes a lean charge entering the cylinder, and is why a choke is used -- it makes the mixture so overrich that it compensates for the puddling.

A hot manifold vaporizes the puddled fuel so the the charge returns to it's indended air-fuel ratio. This is why I agree with the statement that higher temps promote better fuel atomization (in a wet manifold system). In an engine that is warmed up using a cool can, I have to believe that the overall charge is cooler (denser) and any puddled fuel is vaporized back into the charge due the manifold heat.

You can see opposed principles at work here. This is where modern fuel injection systems shine. You can keep the incoming air as cool as possible & not cause leanout due to fuel puddling because you're only porting air.

One of the 'tricks' I did to my C4 is to bypass the coolant feed into the throttle body. Coolant is fed into here to prevent icing on the throttle blades in colder climates-- not really a problem in South Florida where I live. Another 'trick' that the factory did was to use a composite material for the intake manifolds on the C5's. This material has a low thermal conductivity, allowing the manifold to run cooler, allowing the air charge to stay cooler.

Hope I answered your question.

[Jerry Clark]

Re: Need advice on cooling my '88 in heavy traffic

Hi Fred:

Got it, like it, even understand it.

Is the Florida Keys "Corvettes In Paradise" show worth the drive from Tampa?

jerry

[Fred Oliva]

Re: Need advice on cooling my '88 in heavy traffic

Jerry,

Never got down to that show but I've always enjoyed the drive to Key West in my Vette. The drive alone may be worth attending.

If you're not too far from Ft. Meyers, you might want to check out a really good autocross event that they hold there the 1st sunday of every month. Check out www.autocross.com for the details.

There's a woman who attends who's got a real nice original '66 small block that she races. The car is not show car pristine, but she loves to drive it as it was meant to.

Fred O