Glenns72pc Report post Posted October 4, 2014 I have a 1998 Beaver with a 3126 Cat rear radiator. The temperatures run high in the summer on long climbs. Has anyone added a extra transmission cooler to help in the overall cooling of both engine and transmission? Or adding a side louver with a fan to let in cool air from the side of the coach instead of depending on the hot air off the pavement! Share this post Link to post Share on other sites
shields Report post Posted October 4, 2014 Glenn, Cutting in a side vent or adding a supplemental transmission cooler would involve significant effort or expense. Before launching into those modifications, have you considered the more typical solutions? Your underlying problem is high operating temperatures during summer or long grades; both of which add extra strain on the cooling system. With your coach now 16 years old, I would start with the radiator. Has it been carefully cleaned so any road gunk, oil or mud are removed? Once that's gone, take an infrared thermometer and check the temperature all across the radiator; you may find hot spots and cool spots indicating lack of coolant flow and the need for a radiator rebuild. Next, the fan function can be checked, and the coolant itself tested. Finally, the coolant filters might be clogged, or the pump might need rebuilding. Unless your coach has always had high temperature troubles, I'll bet one of these approaches will solve the problem. Good luck. Share this post Link to post Share on other sites
Glenns72pc Report post Posted October 4, 2014 Tried all of the above also run rv at a lower gear higher rpm but still temps creep up !! Share this post Link to post Share on other sites
wolfe10 Report post Posted October 4, 2014 Let's start at the beginning: Have you cleaned the front of the CAC (Charge Air Cooler). It is accessed from the bedroom? Shine a strong flashlight inside the fan shroud. Verify that the perimeter, particularly lower perimeter is as clean as the center (the fan blades sling the dirt to the perimeter). Is you crankcase breather hose extended to behind the fan shroud? If not, you are putting oil vapor (and then dirt) into the CAC and radiator. How old is the thermostat (may have two)? Caterpillar recommends replacing every three years. BTW, Caterpillar calls them "regulators". Have you verified that the water pump belt (a separate belt that is NOT on an automatic belt tensioner) is in good shape and not too loose? Lastly, when you say overheat, how hot are you talking about? And when this happens, what RPM/throttle position are you using? Share this post Link to post Share on other sites
Glenns72pc Report post Posted October 4, 2014 Radiator and intercooler both have be removed cleaned rodded out rad. No blockage found new water pump belts and thermostat installed as far as the temps it rises to 220 and I pull over on flat land it runs 188 200 long hills and mountain passes is the problem trans temp will also mirror engine temps when it get hot I also have synthetic oil in the trans deep sump Allison 3000. Share this post Link to post Share on other sites
wolfe10 Report post Posted October 4, 2014 Yes, the transmission cooler is in the radiator, so as coolant temperature rises, so does transmission temperature. But, unless you allow the transmission to "hunt" between gears (shifting up/down/up/down) the Allison really is not generating much additional heat, as the torque converter is locked up in all gears starting with higher RPM in 2nd, as well as 3,4,5 and 6. Share this post Link to post Share on other sites
Glenns72pc Report post Posted October 4, 2014 If the transmission is taken out of the picture by using a external cooler do you think that will help also adding a large set of louvers and a fan on the side of the coach bringing in some cooler air into the engine area may help What do you think on that change ? Share this post Link to post Share on other sites
wolfe10 Report post Posted October 4, 2014 Were I going to do a modification to increase cooling system capacity, I would put a radiator up front. Use existing hoses to the dash heater. Install valves to divert from heater to radiator. An external transmission cooler would help some, but be aware that an external cooler can OVERcool the fluid in cold temperatures. If you do go with a secondary cooler, route the fluid to it first, then to the OE cooler. I don't think a side scoop would do much-- that fan moves a lot of air and there is enough turbulence under the coach that I doubt it would do much good. And in rain, could funnel water to the engine. Share this post Link to post Share on other sites
huffypuff Report post Posted October 4, 2014 Do you have a side radiator with a 2 speed hydraulic fan motor? If so maybe the high speed is not working or just not turning fast enough???? There has been some on here that has happen to and drove them crazy figuring it out. Share this post Link to post Share on other sites
wolfe10 Report post Posted October 4, 2014 OP said he has a rear radiator. Share this post Link to post Share on other sites
huffypuff Report post Posted October 5, 2014 OK since he has rear radiator and that cat has plenty of toque maybe the engine is being lugged too much causing it to heat up. I have only a Cummins ISC 330 and same transmission with rear radiator and neither heats up on steep grade. It will downshift as I slow down and if it hunts I hit the down arrow till I hit the top. The econ mode is off also and more RPM's blow more air through the radiator. Share this post Link to post Share on other sites
wolfe10 Report post Posted October 5, 2014 Climbing grades, 2000 RPM with your Caterpillar 3126 rear radiator should keep you from overheating. If it does not, then find the problem as outlined in my first post. Share this post Link to post Share on other sites
Glenns72pc Report post Posted October 5, 2014 Adding a radiator to the front of the coach using the heater hoses how big of a small radiator do you think would be need to make any difference ? Share this post Link to post Share on other sites
wolfe10 Report post Posted October 5, 2014 Glenn, I would look at the size and shape of what would fit behind the grill or other location in the front of the coach where it would be in the air stream. Suspect that a radiator designed for even a small 4 cylinder car would be quite adequate as a supplement to your OE cooling system. Share this post Link to post Share on other sites
Glenns72pc Report post Posted October 5, 2014 How would moving the intercooler to the side of coach with vents. And 2 electric fans so the radiator would not have the intercooler blocking it. When I add up the cross tube of the intercooler it = to 1/3 of the radiator being blocked Share this post Link to post Share on other sites
wolfe10 Report post Posted October 5, 2014 Glenns, You are getting into serious engineering issues there. The CFM of your OE fan is HUGE-- too large to be powered by electric fans (at least not from a practical standpoint). Again, the only "reinventing the wheel" that I would do (only after confirming that all the basics are done) would be to add a front radiator using the existing plumbing to the dash heater core. Share this post Link to post Share on other sites
obedb Report post Posted October 19, 2014 I find myself longing for a coach with a side radiator. I wish I had done some research on the advantages. A new owner of a 2002 Foretravel 36ft DP that was factory refurbished before he bought it made me envious. Side radiator resulting in generous access to the engine, as well as a lift able bed that affords generous access to the top of the engine. Seems to me that dirty radiators and charge air coolers would be easily cleaned. Plus two speed radiator fans that can be turned off on cool days saving fuel and turned on in advance of a hard pull. Perhaps problems like Glenn's would be minimized? By the way the 2002 Foretravel was considerably more expensive as a used RV then our 2003 Phaeton. Am I wrong about the advantages of that configuration? Share this post Link to post Share on other sites
wolfe10 Report post Posted October 19, 2014 Agree on the advantages of side radiator: FAR better engine access. Much less susceptible to clogging of the CAC and radiator (cleaner air from the side is pulled in VS "vacuuming the pavement with air under the center of the coach that has dirt stirred up and has gone over hot rear axle, hot transmission and hot engine before being sucked up and forced into the cooling system. And much easier to clean (from the side of the coach instead of accessing it through the bedroom). Better MPG, as the fan is either two speed or variable. Yes, there are a VERY few rear radiator coaches with thermostatically controlled fans-- very few. Share this post Link to post Share on other sites
obedb Report post Posted October 23, 2014 RV diesels seem to develop problems earlier in their life than the big rig engines that I am used to. That observation is based on all that I have read on the internet about DPs. Just throwing this out there: I have heard of water pump impellers on high mileage truck engines corroding to the point that they just aren't moving enough coolant. Not common, but it does happen. Also charge air coolers are a failure item on big rigs. Some are checked as a precaution. Others are checked when serious engine work occurs. Could a leaking CAC cause over heating?? I don't know. Power loss, yes. But? Share this post Link to post Share on other sites
wildebill308 Report post Posted October 26, 2014 I think the OP should be sure his CAC and radiator are clean. I also think if he gears down on climbs and keeps his rpm over 2000-2500 he won't have a overheating problem. Save the money you are thinking about spending on re inventing the wheel and spend it on fuel. Bill Share this post Link to post Share on other sites
manholt Report post Posted October 26, 2014 Glenns. It sure would help to know, where are these long, hot, inclines? I can only think off CA, OR, AZ and parts of NM. Anyway, on a 98' model I would definitely listen to Brett and as far as re-engineering is concerned...don't. KISS, is a good thing! Carl C. 10' AMC Tradition 45' a 425 Cummins 13' Jeep Wrangler Retired Oil Field Trash. Share this post Link to post Share on other sites
