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Trasborgs Kaiser M715 - Jp Magazine

Trasborg's Kaiser M715 - Universal Jeep Cooling Pete Trasborg Brand Manager, Jp trasborg Kaiser M715 hood Opened Front View Photo 9290749

We've all had that stomach-dropping feeling. You know, the one that comes after realizing the engine-temp gauge is in the red-or worse, the feeling that follows when the radiator or overflow tank boiling over from running way too hot.

"The Trip That Never Was" (Nov. '06) was the first indication there was a problem in the cooling system in Trasborg's M-715. Two boil-over overheats and two stops because the gauge was pegged were the indicators. The truck was built during a New Jersey winter and was driven 400 miles in the next year and a half leading up to that trip. In the following year, we learned and relearned more ins and outs of engine cooling than we want to ever again.

Somewhere along the line, we decided all the little things done to the truck (and some we'd done in the past) would make a good story if we stuck them all together.

Look, we aren't gonna spoon-feed you exactly how to fix your Jeep's overheating problems. What we're gonna do is use Trasborg's truck as a canvas and paint a picture of many (if not all) of the typical Jeep enthusiast's cooling-system woes. Use it as a guide the next time your Jeep is running hot and you are 140 miles from home.

PhotosView Slideshow 154 0708 06 z+trasborg kaiser m715+under hood Whenever the water pump comes off, if there is even the slightest doubt in our mind about the condition of the pump, we put a high-flow one in its place. (In this case, the M-715 got a Flow Kooler.) In addition to moving more water, the high-flow units are just flat-out more reliable and built better than most parts store junk. Throughout this thing, we kept hearing people say, "Bet your head gasket is bad." Well, we had no oil in the coolant and no coolant in the oil-we weren't losing any of either. Apparently, you can have a problem and not have leakage or loss. Often, it will show itself in the form of combustion gas in the coolant. This Block Tester from NAPA (PN 7001006) effectively sniffs the coolant to see if you have internal head or head gasket problems. If you've swapped radiator hoses, did you swap the wire too? That wire, which most of us hate, is really a necessary evil. The feed hose (opposite the return hose from the engine) can collapse from suction at higher rpm if there is no spring or wire in it. You'll need to go junkyard fishing if you don't have one. We have made them out of coat hangers in the past in a pinch. If you've already got electric fans and an automatic controller, make sure the fans are coming on when they're supposed to. Toggle your A/C switch or manual override to see if that helps the overheating, or just watch the gauge while idling and see if the fans turn themselves on when the temp comes up. Then came the water-pump issue. We've pulled pumps off Jeeps that had no impeller vanes left. With no idea when the last water pump was put in this engine, we pulled it to check. The impeller vanes were OK, but there was some play in the shaft. File this under "things we never would've thought of without the truck overheating": The 1-inch (or larger) gap between the radiator and the core support can allow air to flow up and around the radiator. The gap was so big that we could drop a screwdriver and it would fall to the ground. When we put the radiator in, we were just worried about the metal destroying the radiator with vibrations. Cappa convinced us to move the sending unit away from the headers for a more accurate reading to the temperature gauge. Before you go monkeying with the sending unit location, if you've got a single-wire unit, put a potentiometer in line with the sender, then turn the knob. With the key in the on position, turning the knob should move your gauge. If it doesn't, your gauge is bad. If it does, you can figure out the resistance at a particular temperature and check the gauge manufacturer or factory service manual to see if it's operating correctly. We fixed that problem with some cut-up fenderwell liners from our YJ. We didn't see a huge difference in this one, but keep it in mind when swapping non-OE radiators into your Jeep. PhotosView Slideshow Some people will tell you that a high-flow water pump and a high-flow thermostat will make the water flow too fast through the radiator and not cool off enough. We aren't buying that. At every corner, we've put in a high-flow pump and these Robertshaw Thermostats, which we got from Flow Kooler. The high-flow thermostats not only flow better, but the action of the valve opening is better-in 10 years, we've yet to have one stick. We installed a pair of Flex-a-Lite universal 16-inch fans. They turned out to be too large in diameter, and we wanted an automatic controller, so we installed Flex-a-Lite's kit made for Chevys that included an automatic fan controller (PN295). Regardless of the part number we used, measure your available space carefully and choose the highest-flowing fan that fits the space. If you install electric fans, make sure they're close to the radiator. Again, not wanting to damage the radiator, we had put Ford Taurus fans on a custom tube mount that ended up spacing the fan blades almost 2 inches from the back of the radiator. This is no good for the same reason not having a fan shroud on a mechanical fan is no good. It will simply draw air from around the radiator rather than through it. Timing: We timed this engine by ear initially. It came to our attention that putting too much timing into the engine, either initially or total timing, could cause overheating. We got an adjustable timing light from Summit Racing and checked it. While a regular light could tell us what the initial timing was, the only way to figure out if we needed different springs or weights in the distributor was to check total timing with the Summit timing light. Turns out, our distributor was OK as it was delivered out of the box. If you're still running an engine-driven fan, make sure the blades are in decent shape, but more importantly, if you have a clutch, make sure it works. Run the engine up to operating temperature by driving it around for a while, then shut it off. The clutch should be engaged at that point and not allow you to turn the fan, or at least provide resistance to you turning it. Most importantly, make sure your fan shroud is in good shape. At one point, when it was hot enough to fry eggs on the power-steering pump, the truck got a B&M Super Cooler for the steering fluid that went in front of the radiator. If your cooling system is marginal, don't put stuff in front of the radiator. The Super Cooler now resides under the bed. PhotosView Slideshow 154 0708 17 z+trasborg kaiser m715+opened hood2 One of the most basic problems: Does your radiator cap still have the chutzpah it needs to keep the cooling system adequately pressurized? Without a decent radiator cap, the answer is most likely no. With no pressure, even a cooling system in perfect shape will boil over. Have your cap tested if you're boiling over and your gauge reads normal. Ever work on your Jeep over the winter? We have. One summer, we ended up with an overheating Jeep and a lot of head scratching. After replacing the water pump, thermostat, and flushing the radiator, we realized the lights we added for nighttime winter wheeling were blocking airflow. Remember that next winter when working on your Jeep. The first step in diagnosing a cooling system is checking the coolant/water mix. Is it clean? Is it green? Make sure it's not rust-colored or that it has oil floating in it. While you've got the cap off, check the radiator cores for blockage. Check out the article "Cool Her Down" (Sept. '05) if you aren't sure what that looks like. If the radiator core is blocked, run a flush through it. If there is buildup in the radiator, chances are the engine has blockages too. Make sure you've got the correct 50/50 water/antifreeze mixture. Admittedly, this was toward the end of the overheating battle. The old flatfender Jeeps had vents cut in the inner wheelwells to assist with cooling, and everyone we talked to with a big engine in an FSJ cut holes in the hood in one fashion or another. We couldn't bring ourselves to cut the hood up, so the fenders got fish gills. The point is, if you've got a huge swapped-in engine or a high-output engine, sometimes the air the fan pulls through the radiator needs an outlet. If you still have the stock engine, it shouldn't have a problem, so look elsewhere. Part of alleviating heat in the engine compartment was applying Thermo-Tec Automotive's Cool-It header wrap. It took us two days to install, thanks to the long tube headers and really tight clearances, but between that and the fish gills, we saw an improvement. Again, this is a swapped-in-engine-toward-the-end-of-the-list thing-unless you just like reduced underhood temps.