[ab1!]

Hello all,

I am about to move from Denver CO to Brownsville Texas, ~1100 miles in a couple months. And I am going to need to tow some stuff down in a u-haul and have never towed anything before, so I need some general advice.

My Rig: 2002 Xterra SE S/C 4x4 Automatic (With Factory Tow Hardware) 145k miles
The truck is in great shape, transmission is a little rough shifting out of first in the cold but super smooth once warmed up. Engine is great, no engines codes or anything except G sensor. Is original engine and trans and everything.
I bought it at 135k, it had detailed maintenance history always done at shops up until I bought it. Even paid for a new knock sensor install (which failed again on me, did the resistor bypass).
Everything is stock, no lift or anything like that. Bad drivers side ball joint I will fix hopefully.

My questions are:
1. Online it says this thing can tow up to 5000lbs. How much would you actually want to tow given my vehicle's condition/age/miles.
2. I do not have any connecting hardware, just the OEM brace on the back with the square adapter, what is a good brand of hitch/ball I should throw on this thing.
3. What important maintenance should I do before this trip. Thinking coolant and transfer case fluid and oil. (everything else has been changed since I bought it).
4. How do I actually calculate how much weight I can put in the trailer given a trailer's weight. The car will be packed with stuff probably as well as towing.
5. What do I not even know that I need to know? Trailer braking, sway control? How do I know if a uhaul trailer has these?

 

[ab1!]

Thanks for all the replies.

So for the transmission oil cooler, would the cooler just be in-line with the ATF fluid lines after the radiator and back to the transmission? Would an engine oil cooler be a good idea too?

And in regards to the KS bypass, I do not think I am going to undo it, considering the very low compression ratio/boost these engines are running, I believe knock is an incredibly unlikely event. I always run at least 91 octane in it, but maybe a compromise for towing could be adding octane booster the whole way?

Thanks to everyone for the other info!

 

[ab1!]

There are 2 lines going to the bottom of the radiator for the trans fluid. One goes IN, one goes OUT. The recommendation from trans cooler companies is to have the fluid go to the radiator first, then to the new external cooler(s), then to the transmission.

So, find the line that pumps fluid to the IN port and reattach it. Take the fluid from the OUT port and go to the new cooler, then run a hose from from the new cooler to the stock trans fluid line.

Make sure that you protect the hoses from chafing, and make sure the new cooler is in the airflow, either by mounting it in front of the radiator or by providing it its own fan, which is what I did.

It is not necessary to use the thermostatically-controlled valve that @JianTao linked, but it won't hurt. Pay attention to the little arrows molded into the housing. I'm using one on my rig.
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Thanks for the info! So to clarify, when you say to “reattach the IN port” you mean just don’t detach it from the radiator? Would you put the thermo-valve before the radiator?

 

[ab1!]

Expect your gas mileage to be really bad. That's just the nature of towing with a first gen Xterra. I towed a Ford Escape on a tow dolly for about 70 miles with my 01 non-SC Xterra. Granted, not near as far as you'll be going, but my experience was it took forever to get up to highway speed, but once at highway speed it did better than I thought it would maintaining the speed on level ground. This is obviously in tow mode. When I say highway speed, I mean 65 max. I think I was between 55 and 60 most of the time. Like the others have said, take your time and enjoy the scenery..Correctly balancing the load in the trailer is very important.

If you're going from Denver to Texas it's downhill most of the way so there is that, lol.

Thanks for the info. Yeah I definitely would rather make it to Texas than crash trying to go 5mph faster. You mentioned you were in “tow mode.” Do these trucks have a tow mode? I did not think they did.

 

[ab1!]

I helped a guy in Aurora, CO diagnose his engine problem. He had caused internal damage by running no knock sensor. He was using 85 octane but don’t be fooled. Operating at 5000+ feet helps prevent knock. You’re dropping in elevation and towing a trailer. Your engine is going to be experiencing more load than it’s probably ever seen. If you’re stuck on not installing a knock sensor than I would AT MINIMUM remove the resistor while you’re towing.

A convincing argument… I definitely would cry if I ruined my car. Do you think there would be any side-effects of running under high towing load with adjusted timing?

 

[ab1!]

It allows 10% to pass through at all times, and gradually increases that as the temp rises. I can get the TC to lock immediately while it is still cold. The freeway is only 1 mile from my place, with only 3 traffic lights and 2 stop signs in between, so I don't think it warms up enough to consider it as being at normal operating temp in the trans. And for sure the engine doesn't warm up fast!

You have a 50-50 chance of removing 1 line and it being the OUT port. If you remove both to see 1 pumping out and the other trying to suck fluid in, then the one pumping goes to the IN port (they're not actually labeled, but I'm referring to them to keep the lines identified). If you didn't take it off, then yes, it stays put.

Then you take the fluid from the OUT port to the other cooler, and then to the remaining trans fluid line that used to be on the OUT port.

Stock:
From trans IN --- Rad --- OUT to trans

Extra cooler:
From trans IN --- Rad --- OUT to extra cooler --- to trans

Extra cooler with thermo valve:
From trans IN --- Rad --- OUT to thermo valve --- to extra cooler --- to thermo valve --- to trans

The thermo valve unit has 4 ports. It comes in one port and the thermo valve allows 10% to go to the new cooler, while 90% makes a u-turn back to the transmission. The other 2 ports go to the extra cooler and are controlled by the thermo valve. When the temp rises, less makes the u-turn to the trans and goes to the new cooler.

I would not recommend placing it before the radiator, since the system is designed with it going to and from the rad with no re-routing. However, I also don't see it as hurting anything, but I'll let others weigh in on that.

Ah okay perfect, thank you. That is very clear so I think I will try this out. Probably not going to go with a valve because… Brownsville is crazy south, but if I end up back in Colorado i think that’d be a fun mod.

 

[ab1!]

I would pack a extra distributer, and bring a OBD2 reader, and be prepared for something to break, as long trips can be rough on a vehicle, look the vehicle over, monitor tire pressures, and check fluids religiously for the duration of the trip.

That Supercharger is going to handy for the extra load.

Yeah I am planning on at least this. I have a BlueDriver so I’ll be checking that periodically as I go. I’ve heard you should only ever get the OEM dizzies. Would you agree with that? They are pretty expensive.

 

[ab1!]

@ab1!, not a mechanic and certainly not as knowledgeable as Blackberry but in your position if you're not gonna bypass the knock sensor, do the following things:

Set your timing between 6-8 degrees -- I think stock is 10. I have mine set at about 12 and I have no issues.

Run the highest test gas you can for the drive down, and put a can of octane booster in there. If the octane booster is too much, consider getting PURE toluene, which is Octane 104. It's obtainable at paint stores:

Toluene - additive for racing fuels, fuel octane booster

Toluene is an aromatic hydrocarbon solvent often referred as methylbenzene. Toluene is widely used in industry, often served as a substitute for benzene. Methyl side groups present in toluene makes toluene metabolized differently than benzene. Toluene is well absorbed through the lung, with a...

www.worldofchemicals.com

Gen 1 Xterras have metal intakes so diluted properly this will not be a problem, AFAICT. I am not responsible for motor damage.

But, more seriously, do a proper knock sensor. At least locate it somewhere on the back of the block or extend the wiring to the front of the block. Just don't bypass with a damn resistor... That's asking for trouble and if you run 85/87 while towing, even with retarded timing, kiss that motor goodbye.

I assume to set timing I would have to take the timing cover off to rotate some things? Or is this something that can be done electronically with spark timing or the injectors or something not under the cover?

 

[ab1!]

My take on doing a radiator flush before a trip: Don't do it!

I had 2 bad experiences when doing that, several years apart. Both times I was quite a few hours from home. Both times, the water pump failed. Both times, the pump was older but not leaking. Both times, the schmutz that had gathered around the bearing seal was flushed away, and not long afterward the bearing failed.

If you just gotta flush your coolant, my recommendation (for any vehicle, not just the Xterra) is to replace the water pump, all hoses, and t-stat.

Either top off the system, or replace all parts with pliable components, such as hoses, seals, etc.

I was definitely going to change all the coolant since cooling is a big limiting factor with towing… this sounds pretty time consuming and expensive to change all of that.
has anyone else experienced this?

 

[ab1!]

Well there are two ways of doing it to my knowledge.

They make water hose connections.
And additives that you drain out.
I wish I could elaborate more but I gtg.

My plan was just to drain all the coolant out and then just fill it up again. Hopefully with the right stuff! I had poured some generic “asian blue” that said it covered Nissan in 2002, but I have no clue if that is actually how it works.

 

[ab1!]

I actually meant the OD on/off button on the left side of the gear shift lever. Basically the same thing as tow mode. If you're towing, you want OD turned off.

Why would you want O/D off for towing? It just doesnt let you go into 4th right? Wouldn’t the trans shift down if I needed more power?

 

[ab1!]

Correct, but all that shifting will make the trans heat up and a lot of stress on that fourth gear. it's the main reason for the O/D off so that the torque converter will lock in in 3rd allowing better towing, I would use it when going through hilly areas.

O okay that makes sense. I guess I should just accept the low MPG and not try to stress the trans out.

I am going to get going on a trans cooler soon, do I have to add additional trans fluid because of that extra volume in the cooling loop? Or would the normal dipstick level still be accurate because it would account for that change in volume?

 

[ab1!]

I'm actually looking into eventually talking with an embedded friend of mine to see if we can build an open source ECM.

I would think though that it would mostly be solder joints that fail -- if you can solder that's an easy fix. Just make sure to use the good stuff with lead, the unleaded stuff gets tin whiskers in hot conditions BAD. That's a reason XBOX 360s died so easy.



No,get a timing strobe, look up how to use one and read markings, then do about 6-8 degrees BTDC. But honestly, it's too much work. Pull the plenum and put in a real K/S.

Never! I am starting an anti-knock sensor religion.