I am adding a tranny cooler - do I need an oil cooler also?


#1

I have a 2004 Ford Frestar , 4.2L v-6 that does NOT have the tow package. The Freestar has a tow rating of 3500 lbs. I am going to be buying a boat this summer that with trailer and fuel will weigh about 2800-3000 lbs. I am going to add a transmission cooler, just to be safe. Should I purchase a dual purpose cooler that cools both transmission fluid and engine oil?



Thanks for your insights!


#2

You can answer the question two ways,you can say add the oil cooler because cooler oil is always better.

Or you can look at the specs,how much cooler will the oil be,is the 4.2 Ford operating on a low volume of oil to start? What is the cost? is (X) reduction in oil temp worth (y) dollars? Does the 4.2 come with any type of oil cooler from the factory? does it have a aluminum finned oil pan? Could the oil cooling issue be addresed by a larger radiator (lowering overall temp)

Will the addition of the oil cooler increase the number of possible oil leak points?


#3

Ok, not much info to form an opinion. Let’s assume that you plan to hook up the boat and head off for the weekend meaning a car full of family and gear with another 3,000lbs or more in tow. You are going to be driving on expressways and will encounter some hills along the way - yep I’d go for the oil cooler too.

Towing under the above circumstances is MUCH more load on your engine and transmission. I’m amazed when I see folks with big trailers bombing along at 80 mph. You are pretty much at the limit of the capacity of your vehicle so give it all the cooling capabilty you can. Your standard radiator is not up to the load either, you should consider fitting a larger radiator. You are going to be doing your towing in the summer. Imagine a hot day, at 65 mph going up a long hill with the AC blasting away. This is max. stress on your car. When towing I strongly recommend you use full synthetic oil.

My boat is about the same weight as yours. My car was a Volvo wagon rated for 3,500 lbs. I figured the towing would KILL the car, so I traded for a Toyota Sequoia. You may get by with your car, but you may consider getting something that has a factory tow package installed already.


#4

I’ve had several cars with “trailer towing packages”. They never included an oil cooler. The inside of the engine is always hot, and having your coolinfg sysytem is good shape is the key. Trailer packages always have a heavy duty radiator.

It is very important to get a really good oil of the right viscosity. A sure way to wreck your engine is to use cheap 5W20 oil, as recommended in most Fords, and really overload the car. A friend of mine pull a heavy 5th wheel camper with a Ford F150, and he uses 15W40 oil, the same as rated for diesel and gasoline (mixed fleet type). The key here is film strength; if you really want to be sure use 10W30 full synthetic, such as Mobil 1.

In short, you don’t need an oil cooler, but your cooling system should be clean and you need a heavy duty oil in your crackcase.,

Happy boating!


#5

How far will you be towing? What kind of roads and hills? Loaded up with other cargo?

If its just across town to the boat ramp, I say no. If its a long tow to a mountain lake then I might go for it. Find a good trailer shop and get their input. Does it have coolant temp gauge? Keep an eye on that…that could be an indicator for installing an oil cooler.

Also look into trailer brakes.

EDit: Geez the other guys type faster than me! But we agree it depends on you usage"


#6

If you do not have an external line for the motor oil to run through, and potentially leak, why add one? The benefit will be minimal IMHO, but the liability too great.


#7

It certainly is an extra thing to go wrong as Busted pointed out. It is impossible to give a generic answer to the question. The bottleneck to getting heat out of an engine is going to vary from vehicle to vehicle. With some, it may be the size of the radiator, with others it might be the coolant flow from the engine to the rad and back. With still others, transfer from the engine block to the coolant might be the problem. If the air flow is the issue, blocking it with an oil cooler is not going to help you. I would give it a go and watch the temp gauge. If it rises past where it generally does, you know you need help. Of course, all you need to do is slow down.

Be careful about installing the trans cooler. Do you have a separate oil to air trans cooler from the factory? If so, the oil flow might be controlled by a thermostat. It is on my Mercury. Swapping in a bigger, uncontrolled, cooler could give you trouble in cold weather. I would not put a second cooler in series unless you are prepared to verify that pressure and flow back to the trans are not compromised. A second cooler in parallel should be fine, and you might be able to install a valve to shut it off when it is cold and you are not towing.

BTW, the Motorcraft oil recommended by Ford is a good quality semi-synthetic. Their filters are good too. Larger than standard radiators are not nearly as available as they used to be. Often they need to be custom made.


#8

I should point out that transmissions used in the Taurus and Windstars were never particularly stout. My family had a 1995 Windstar, a 1995.5 Windstar, a 1998 Winstar, a 2001 Windstar, and a 2003 Windstar. The 1995, the 1999.5, the 1998, and the 2001 all had transmissions let go around 60k miles. There’s the whole head gasket thing too, but that’s another rant. Even though the later Windstars got the better AX4N transmission. I would not trust it to tow anything. Not a simple 6 foot lawnmower trailer, and certainly not a boat. I would add the biggest, nastiest transmission cooler you can find and even then I’d throw a rabbit’s foot in the glove box and make sure the stars are aligned. before I would tow anything behind a Windstar/Freestar.


#9

If you are worried about the oil lubricated at higher temps I would use synthetic and forget about an oil cooler personally.

Realize this is severe service so check manual carefully for maintenance guidelines.


#10

Thanks for all of the responses! Here is some additional information. Im the engine I run AMSOIL oil with an AMSOIL EaO oil filter and a filtermag on the filter. It is a factory oil pan - no cooling fins. I just put a new radiator on it and had the cooling system flushed. I will have the family and all of the gear in the van as well as towing the boat. Our cabin is about 100 miles away and we will probably make a dozen trips there this summer, with boat in tow.

Thanks again!


#11

I bought the 2002 Highlander 2wd with tow package and towed a 4700 lb total load of boat and dual axle all alum, cast wheel, trailer with brakes and the boat was a 24’ boat on a 30’ trailer and then my little 19 foot Highlander pulling it all. I went to Knoxview from Jacksonille Fl. and managed to drive through Atlanta in the rain at rushhour night as long as a semi. I drove with absolutely no probems and often checked the fluids but toyota tow package was top notch. I got about 13 mpg when using just 3rd (would never lug the engine) and about 17 when in 4th. That was 90+miles ago and the tranny is still perfect.


#12

The more coolers the better, it can’t hurt but only help. Be aware there are different capacity coolers, so pick the best!


#13

According to the 2004 Ford Towing Guide https://www.fleet.ford.com/showroom/rv_trailer_towing/2004/2004_default.asp , Your van only has a 2000lb tow rating; https://www.fleet.ford.com/showroom/rv_trailer_towing/2004/2004RVTrailer_Freestar_Eseries.pdf

Not saying you don not have different info, but from what I see you will be overloaded


#14

For what it’s worth, Ford Crown Vics with the P71 package (police) have BOTH a tranny cooler and engine oil cooler as part of the package. If your tow is 50 miles or less, I would not worry about either. But for longer distances, I would give your engine and transmission all the help they can get…When towing FOR SURE lock out the overdrive and 60-65 is PLENTY fast enough…


#15

Thanks for the finding that information! My Freestar has the 4.2L V-6 and I have found that the 3500 lbs rating is if it has a tow package and 2000 lbs if it does not. This is what inspired me to seek your help to begin with: what changes do I need to make to equate to a “tow package”? I added a class 3 hitch and wiring harness a year and a half ago and have been pulling a small utility trailer rated for 1000 lbs with ease. I know i need to add the largest tranny cooler I can find, but am not sure if a engine oil cooler is needed to complete the package.


#16

I still do not see the trailer wgt limit to be above 2000lbs based on the Ford info. I am not a towing expert, but from what I can see you may be seriously overloaded with a 2800-3000 trailer, all your passengers and the cargo weight of their gear for a weekend trip. Your brakes will be working very hard even if you can get trailer brakes on a boat trailer.

I tow a car, trailer, and gear combo of 5000+ pounds. I was very happy when I lost my trailer brakes and had the F250’s heft and brakes to control the CVW of 11,960lbs.

I urge you to seek the advice of a trailer shop. Sorry to “preach”, but not knowing your skill level I am trying to be the word of caution. I have heard many times that the most dangerous part of a weekend racing is the towing the racecar.


#17

Like racer, I also worry about loading up your trailer and perhaps overtaxing the brakes and certainly the transmission, even with a transmission fluid cooler. Some time back I talked to a tow truck driver who lives near a freeway with a very long uphill stretch. His most frequent tow is any Ford minivan, from the Aerostar through the Freestar. And it’s always the transmission! Like racer, if you are interested in serious towing, get a rear drive vehicle with a sturdy transmission. A Ford F150 with an extended cab will tow a great deal, as will a suitably equipped Crown Victoria(especially the Police special).

I have always towed trailers with rear drive vehicles. The posters here are trying to keep you out of serious trouble. A competent trailer/hitch shop can tell you exactly what you need for trouble-free trailering!


#18

The hitch and wiring harness are the “minor” parts of the tow package supplied by the mfg. I don’t know the specifics for your year Freestyle, but typically a factory tow package incluedes a larger radiator, larger cooling fans, heavy duty alternator, motor oil cooler (sometimes incorporated into the larger radiator, sometimes separate), transmission fluid cooler and heavy duty suspension. Sometimes the package includes larger brakes, larger wheels and higher capacity tires, and increased flow water pump.

When you put the tongue weight of the boat trailer (likely a lot higher than your utility trailer) on the hitch you’ll see a significant drop in the height of the rear of your Freestyle. This can alter handling and braking significantly. It also unweights the front end of your car, which is the drive wheels. When you back the boat trailer down the ramp, no problem. When you go to pull the boat out of the water, if the ramp is steep, if it is wet, and if has dirt and sand on it (not uncommon) you are going to have some traction issues. Pulling the boat out will be very tough on your transmission.

If you said you were using the car to launch the boat once or twice a year and drive short distances at 30 to 50 mph I would say you could get by with your vehicle. You said you were driving about 100 miles with a full family load plus the boat to your lake house on summer weekends. This does not sound good to me. Can you store the boat at your lake house? Can you store it somewhere near the lake (marina, or U-Store It place)?

For these weekend trips your trailer needs to be in top shape. The surge brakes need to work well. Without trailer brakes I won’t attempt highway speeds with your car. Braking will not be safe. Someone suggested a different vehicle, and I agree. Your car has a towing capacity of 2000 lbs. Adding the biggest oil cooler and tranny cooler you can does is not the same as a factory tow package. You might get away with it, but it will be sketchy at best.


#19

Thanks for the information and advice. I don’t take this as “preaching” as referred to in an earlier reply. I take this as wisdom, which is what I was seeking. I will go to a Ford dealership and a trailer shop and seek their advice.

Thanks!


#20

To find out some of the things included in a tow package you could consult on-line parts sources. See if they list two items for your vehicle, one with tow and one without, springs, radiators, as Uncle Turbo listed. I would add a couple of items. Lower axle ratios and bigger engines correlate with higher towing capacity. I think a Freestar board might be an easier way to figure it out. Someone might have a copy of the ordering guide for your year.

P.S. A google search yielded lots of information: ford freestar “tow package” OR “towing package” 2004