CoolingCooling TipsTips FromFrom

troubleshooting chart road that’s more sensitive to cover, nor a radiator by its size. Visteon’s can keep you from performance, and replacing one takes Paul Verdile told the 2000 NARSA skipping important di- about six hours of R&R labor! Eating convention that to meet its cooling agnostic steps, but real- six hours of labor is not something you performance specifications in even world answers to spe- can afford to do if you intend to run a tighter underhood packages, Ford is cific problems often lie profitable shop. installing two new-design . in the details. Attendees at the semi- NARSA announced that it’s joining They may look like less, but actually of- Anars and trade show of the 2000 con- the industry consortium of MACS and fer equal or more cooling than heavy- vention of the National Automotive the Performance Review Institute of duty designs. Radiator Service Association (NARSA) SAE to provide technicians with per- A two-row radiator typically is a learned how to keep cooling systems formance, durability and fit guidelines high-performance replacement for a running cool in summer and pumping for automotive heat exchangers. The one-row, but Visteon’s new 26mm one- heat into the cabin in winter—on program, which the participants hope row rad has dimpled tubes (which everything from to big rigs. will be operating within a year, is in- break up the flow for improved The news out of the show concerns a tended to rate all replacement heat ex- heat transfer) and high fin density—19 number of topics—radiators, pressure changers against OE specs for heat fins per inch. This compares to the tra- testers, thermostats and heaters. There’s transfer, durability (such as salt spray ditional 52mm-thick core—two rows a lot to cover, so let’s get on with it. and pressure cycles for radiators) and of conventional 26mm tubes and 10 proper fit (for example, does it go in fins per inch. The new 26mm one-row, Radiators without cutting and welding on which is being phased into all cars and You can’t afford mistakes with radia- adapters?). many light trucks, beats the 52mm on tors, because today’s high-tech heat ex- With many radiators that are any- heat transfer for all airflow rates and all changers are more expensive than ever. thing but an easy R&R, it’s doubly im- coolant flow rates except the lowest A late-model OE Taurus radiator lists portant to avoid comebacks. So if you (see the graphs pertaining to the Ford for more than $300, unless you can do use aftermarket radiators, you want to Explorer on page 24). However, overall better in the aftermarket. But you’ve know they’ll cool properly under all performance is equal at idle and better got to be very careful about what you operating conditions. for trailer-towing and other high-load buy. Taurus is one of the cars on the You can’t always tell a book by its applications.

22 August 2000 The annual National Automotive Radiator Service Association trade show provided its usual blend of good general tips and specific new applications for keeping things cool when temperatures get hot.

BY PAUL WEISSLER

A new 36mm “B” tube—with fold- ing process—called CuproBraze—is quire specific downflow radiators with ed-over ends welded at midpoint, cre- very similar to what brought success to PTO openings, and a new aftermarket ating two flow paths, in the shape of the the modern aluminum radiator. It uses source—Behr Heat Transfer Sys- letter B—is the heart of a new one-row a greater temperature range for manu- tems—introduced both this type of ra- radiator Ford is now is installing in F- facturing effectiveness than convention- diator and a crossflow with PTO open- Series pickups and Expedition/Naviga- al aluminum processes. So it permits ing for tilt-hood models. tor SUVs. It replaces the old two-row, smaller aftermarket manufacturers to Jeep Cherokee Radiator. There 52mm job and, except for one small produce quality copper/brass radiators should be no problem getting a radia- coolant flow rate area where the two- at lower cost. tor for a Jeep Cherokee, but there’s an row is slightly better, the one-row is far Copper/brass still dominates the exception—the right-hand-drive mod- superior (see the graph on page 24). heavy-duty and low-price ends of the els sold for postal delivery applications. The bottom line is, you can’t tell a automotive aftermarket. With Cupro- This radiator is not the same as the one radiator’s performance anymore just by Braze, however, copper/brass radiators in LHD models (which won’t fit) and looking at it, or even by measuring or now can compete in the same market as isn’t readily available for a low-volume counting the number of tubes. Until the best automotive aluminum types. model. An all-copper/brass radiator the new rating system is in effect, play The pioneer in this area is Universal drop-in replacement for the aluminum it safe by sticking with the reputable Auto Radiator in Pittsburgh, a medium- core/plastic tank unit in the RHD aftermarket brands (or OE). size aftermarket manufacturer working Cherokee was introduced at the show CuproBraze Brazing. The copper with the assistance of the CDA. by Tanks ’N Tabs, a leading aftermar- industry hasn’t just watched its automo- Heavy-Duty Alternatives. It’s of- ket parts supplier. tive radiator business go down the tubes ten difficult to find aftermarket re- (no pun intended). The Copper Devel- placement radiators for medium- and Pressure Testers opment Association (CDA) has been heavy-duty applications, which (along Saving money on no-name parts or funding development of lightweight, with cost) is why NARSA heavy-duty trying to modify a “universal” radiator solder-free, high-performance and— specialists can keep busy with repair to fit are mistakes a journeyman pro- most important—durable copper/brass work. The pre-1995 medium-duty fessional shouldn’t make. But today alternatives to aluminum core construc- Ford trucks with Cummins engines, you can go just as wrong with stan- tion. The furnace-brazing manufactur- power takeoffs and alligator hoods re- dard-duty parts for heavy-duty situa-

August 2000 23 COOLING TIPS FROM NARSA

Heat Transfer Performance Curves for 1-Row & 2-Row Radiators 40 40 1-Row, 26mm, 1-Row, 26mm, Dimpled-Tube 35 Dimpled-Tube Design 35 Design (19 fpi) (19 fpi) 30 30 25 25 20 20 15 15 10 2-Row, 26mm 10 2-Row, 26mm Design (10 fpi) Design (10 fpi) 5 5 Heat Transfer Capacity (J/s/cm^2 0 Heat Transfer Capacity (J/s/cm^2 0 Air Speed (m/min) Coolant Flow Rate (kg/min) As the chart on the left shows, the new one-row, 26mm dimpled-tube Visteon radiator outperforms two rows of conventional 26mm tubes at all airflow rates. As seen in the chart on the right, except at very low coolant flow rates, the one-row Visteon radiator also outperforms the two-row in coolant flow testing. Overall, even at idle, the one-row radiator’s performance is better. These particular graphs apply to the Ford Explorer. Source: Visteon tions and last year’s parts on this year’s heavy-duty thermostats (the heavy- cause overheating? Evidence says it model. Peak cooling system tempera- duty power valve is larger in diameter can be a major contributor to a cool- tures are on the rise—almost 300°F and the stat spring is much beefier), ing problem. (with systems pressurized to 25 psi) so don’t skimp against your or your A number of vehicles with inlet since ’99 on some GM trucks, Chevy customer’s “better” judgment. A stan- thermostats (at the coolant entry into Camaro, Pontiac Firebird and dard stat valve will bounce closed and the block) have housings with the Corvette with the new family of open, and won’t maintain stable thermostats staked in place and O- pushrod V8s. These high-temperature coolant temperatures, particularly un- rings or gaskets preinstalled. These systems are just the beginning, as the der heavy loads. Is this enough to stats, which have specific opening cal- vehicle makers work to lower exhaust emissions. The new GM systems have forced Heat Transfer Performance Curves for shops to upgrade their pressure testers Ford’s Light-Duty F-Series Pickups to the 30-psi level. But, although the cooling systems on these vehicles have been designed for the higher pressure, explained Gary Baseley, a Stant train- 32 ing manager, at the convention, he 1-Row, 36mm Radiator cautioned techs not to go more than about 2 psi over the cap specification. 28 Carelessly using one of the new testers and pumping up to 30 psi could “blow the seams” on a marginal radiator or 24 heater core, he said. Thermostats 20 The heavy-duty thermostat used to be something you’d install for a customer Heat Transfer Capacity (J/s/cm^2 2-Row, 26mm Radiator with a motor home if he were vaca- 16 tioning in the mountains. With today’s Coolant Flow Rate (kg/min) systems, though, it may even be stan- The new Visteon one-row, 36mm “B” tube outperforms the two-row, 26mm dard equipment on some vehicles, radiator except for one small area of the coolant flow rate chart. It’s clearly Baseley said. You can easily see the better in the more critical low-flow and high-flow rates of operation. difference between standard and Source: Visteon

24 August 2000 Photos: Paul Weissler Paul Photos: A competitive aftermarket line of crossflow (shown) and When the thermostat is built into its housing, as shown downflow radiators for Ford medium-duty trucks with here by MotoRad of America (’99 GM V8 at left, ’95-on Nis- Cummins diesel engines is being offered by Behr Heat san Maxima and ’01 Pathfinder V6s at right), don’t try to Transfer Systems. These radiators include a power take- get it out and substitute a conventional stat. The preat- off opening in the mounting member, seen at the bottom. tached O-ring/gasket is also part of the package. ibrations, are used on sensitive en- to their lines, so don’t ever try to dig Pontiac Fiero, Toyota MR2 and VW gines. If they shift out of position dur- the old stat out of its housing and in- Eurovan. Today, there’s hardly one ing installation, however, they could stall a universal replacement. You’d that’s easy, particularly with the relo- adversely affect the coolant flow pat- just be asking for trouble. cation of the fill cap to a separate tern. The thermostats themselves are pressurized reservoir or—the newest of the bypass type, so a replacement Filling the System location—in the upper radiator hose. needs the right-size valve to assure Some cars’ cooling systems have long Just jacking up the front of the vehi- proper coolant flow. Aftermarket been known as notoriously tough to cle until the rear bumper hits the thermostat suppliers have added them fill—for example, the ones on the garage floor may not work. The companies are using air bleeds in- creasingly, which you have to find and open. They used to be strictly on the engine, and occasionally in an upper radiator hose or hose neck. Now they might be anywhere, with the heater lines becoming a popular spot. A new entry in the tough-to-fill category is the Lincoln LS, and each of its two different engines (a V6 and V8) re- quires its own special techniques. You might think the V6 is routine, because it’s the familiar Duratec en- gine. But be careful, warned Paul Verdile of Visteon. Both V6 and V8 models have one air bleed in a heater line. On V6 engines only, there’s a second one in the crossover pipe at the top front of the engine. On V8s, there’s a coolant fill cap on the engine (under the beauty cover). You might not look for it because there’s also a pressure cap on the coolant reservoir. On Lincoln’s new LS, there’s an air bleed built into the heater hose located By the way, that beauty cover is between the brake master cylinder and the coolant reservoir. held on by three “Christmas trees,”

August 2000 25 COOLING TIPS FROM NARSA and only one is the type that pops off easily. Figure on breaking the other two and have spares handy. (Guess how we found this out?) First, add as much coolant as you can to the reservoir fill (slowly, please!). Next, remove the engine fill cap (which has a 10mm Allen head) and add as much as you can there. Reinstall both caps, but leave the heater line air bleed open. Run the engine at idle with the HVAC control head temperature set to 90°F. When a steady stream of coolant flows from the heater air bleed, shut it, but let the engine continue to idle for five minutes or so. Open the heater air bleed again mo- mentarily to let any air trapped in that area escape. Top up the reservoir, run On the Lincoln LS V8, remove the beauty cover as shown (probably breaking a the engine at fast idle, set the controls couple of “Christmas trees” in the process, so keep some extras on hand) for for 90° and check to see if the floor access to the coolant fill cap. A 10mm Allen hex holds the cap on. ducts are blowing acceptably hot air. If they are, you not only have some assur- form) can use a premium all-electric up, for example, the fill cap is on a ance that the heating system will be fan at lower cost, why not Lincoln? neck spliced into the upper radiator okay in winter, you also know that the Other vehicles have their special hose. air pockets are out of the cooling sys- designs, as well. With the general low- A new approach to purging air from tem, for good summer cooling. Let the ering of front ends, the radiator fill the cooling system—adapted from a/c system cool down and top up the neck usually is off the radiator, the service—was exhibited at the NARSA reservoir again, if necessary. separate, pressurized reservoir being trade show. Called the AirLift, it was Important caution: The Lincoln LS the most popular alternative location. developed by Uview Ultraviolet Sys- V8 has an electric auxiliary water pump And on the new Dodge Dakota pick- tems, a maker of a/c trace dye service that’s mounted in front of the radia- tor/condenser module (behind the grille) and wired through a relay to the powertrain computer. The computer, which also reads a pair of cylinder head temperature sensors, can turn on this electric pump to increase coolant flow, if necessary, for periods of up to five minutes. If you ever need to check the pump, make sure it’s connected to a source of coolant—even for just a quick check. If you inadvertently run the pump dry, it fails very quickly. The computer also controls the speed of the hydraulic fan motor via a duty-cycle solenoid valve that’s located between the engine-driven oil pump and the motor. It’s a quiet design that permits infinitely variable fan speed, and has been used on the Lexus LS 400 for years (and even briefly on the Toyota Camry). But it’s expensive and Connect your shop’s air line (red hose) to Uview’s AirLift, which uses a ven- may be a one- or two-year wonder for turi effect to create vacuum and pulls down the cooling system. Then hook up the Lincoln LS. After all, if the Jaguar the refill hose (green), insert the other end into a container of fresh coolant S-Type (the sister car on the same plat- and open the service valve. The fresh coolant will be drawn into the system.

26 August 2000 a/c reheat in summer, but a leaking heater still is a coolant leak you have to fix. However, as ACDelco’s Charlie Fewell told convention attendees, you’ve got to find the cause of a leak. If it’s corrosion perforation, there’s a chance the coolant itself is bad, in which case the system will need a complete flush and a good fill to pre- vent a quick reoccurrence. Also, check for coolant electrolysis. If a voltmeter probe inserted into the coolant reads .3 volt or higher, there’s a defective ground somewhere that can corrode the radiator and/or heater core. For packaging and line consolida- tion, Fedco heater cores are starting to come through with detached neck tub- ing. If you lube the tubing O-rings with Replacement heater cores from Fedco Automotive Components are starting to coolant and install the necks and snap come through with detached hose necks (right). The new design lowers costs rings carefully, the O-rings should seal by reducing package size and permitting some part-number consolidation. as well as brazed-in-place tubing. Be- cause the necks can rotate, they may kits and oil injectors. Basically, it’s a 25 to 26 inches of vacuum. This isn’t a even make the heater core, with its venturi-type vacuum pump, much like deep enough vacuum to boil even precisely bent tubing, easier to install. the inexpensive a/c vacuum pumps plain water, so it pulls out air only. Lexus has used detachable necks with that run on shop air, plus adapters clamps for years without incident. And that allow it to fit most cooling system Heaters Fedco is a large manufacturer for the fill necks, including Japanese models. It may be midsummer, but the heater aftermarket (under the Modine brand) It’s intentionally designed to be some- is a year-round part of the cooling and and OEMs. what less effective than the best of a/c systems. A customer may notice in- You’re probably some time away that design, so it draws no more than adequate heat more in winter than for from your first Lincoln LS heater core, but this car’s HVAC system uses an electronically controlled heater control valve instead of the traditional flap doors. If you ever have to check the system, this NARSA convention warn- ing from Visteon is worth remember- ing: The valve’s harness connector ter- minals are very close together. If you’re not careful during service and create a short circuit, you can kiss the HVAC module goodbye. The margins for error in cooling sys- tem service are getting smaller, as elec- tronic controls take over and the coolant runs at higher temperatures and pres- sures. But hey, it’s all part of the com- plexity of driveability diagnosis, and some thermodynamics, too.

For a free copy of this article, write to: Fulfillment Dept., MOTOR Magazine, 5600 Crooks Rd., Troy, MI 48098. Additional With the O-ring installed against the flange on the hose neck, insert the detached copies are $2 each. Send check heater core tube into the core tank flange (left). Then secure the neck with a or money order. snap ring (right). Because the tubes can turn, installation should be easier.

August 2000 27