98 SOHC running hot, looking for upgraded radiator advice

[Justin_]

Hey guys, im back to working on my 98 SOHC w/auto trans again.

This time im looking to address heat.

Recently I took a 2000 mile trip down to Las Vegas to attend a cyber security conference and had a great trip. The truck ran well with one exception, it got HOT.

For a better part of the trip between Salt Lake City and Las Vegas I had to keep an eye on the thermostat gauge to make sure I was not overheating. Most of that part of the trip I ran between 'Above normal' and 'Uncomfortably hot.' I did manage to keep the gauge below vertical the whole time, but had to slow down quite a bit at times. I wouldn't blame the engine as the ambient air temp was as high as 118F, the AC was all the way up, and the highway was going 80 on hills, but I would like to minimise this.

I have also noticed this once closer to home when I had the cruise control set at 90/95 and it charged right up a steep hill at full tilt. Im sure my 4.10 gears are not helping me here.

In the last year or so I replaced the thermostat+ring, rad cap, and coolant. When I replaced the coolant it was just because I had to pull the rad during the body swap. The coolant was super clean when I drained it so I don't think there is much/any buildup in the engine.

This has lead me to looking at new/upgraded rads. I don't have much experience here (Well, there has yet to be a car thing that I have had experience on when jumping into it ) but it looks like I should try to grab an all aluminium rad with 2+ cores. I do know that there is an aftermarket trans cooler installed so I don't need to worry about trans line compatibility.

Should I just go for an all aluminium 4.0 rad, or is there any advantage in using a 5.0 rad?
Is there anywhere that sells a trans-less rad, or is that even something I would get better performance out of?
Is the stock rad copper/brass? Will I get better performance out of a typical aluminium radiator with plastic tanks, or should I just go full aluminium?

I see that Radiator Express has an all aluminium rad. It's a bit expensive at $230+$25 shipping. Im not against spending the cash, just looking at comparing my options before I do.

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A few other things to note, I do not have a fan shroud. There was never one on the truck from when I got it, and it has a 3" BL so I don't know if one would fit. Also I have a winch blocking part of the rad for what that's worth.

Please do let me know if I am looking in the right direction.

 

[BrooklynBay]

The fan shroud directs the air flow, so you should try to get one. It's also a safety issue since the blades are exposed without it. Did you check the fan clutch to see if it's slipping? Do you know the temperature range of your thermostat?

 

[donalds]

Got to get you a fan shroud
I'm wondering why it DiD not overheat

 

[CDW6212R]

The OEM trucks have shrouds and air diverters on all possible sides of the radiator, the rear one, the bottom one, and the two side pieces. With the huge air blockage in front, it is lucky that it didn't overheat.

You can install the bottom air deflector on that truck, that space under there is still unused. That stops air from going under the radiator. You have to have one for the fan. The two side pieces are flexible and easy to yank off or get lost. Fixing the air flow controls will help a lot, do those for sure.

You do not want a 5.0 radiator, those are no better, and they are made to hold the condenser also. The V6 radiator is the one to use for all 2nd gen Explorers, with the V6 lower condenser bracket.

If you force the air to go through the radiator, then a full thickness unit will be best. Without proper airflow, no radiator is going to fix it. I'd like the AL kind, I haven't gotten to that myself yet.

Add a bottle of Water Weter or similar additive, those reduce temps slightly, enough to notice barely on the gauge. Mine runs well below the middle with a 180* I put in two months ago, with a new timing cover gasket and WP.

 

[C420sailor]

90-95mph up a steep incline in hot weather with no fan shroud and a massive source of restricted and turbulent airflow in front of your grille.

I’m with Donalds. I’d be more surprised if she didn’t get hot as ****.

There are people on this forum who live in Kuwait and drive vehicles with stock cooling systems. The key is to maintain the system (to include having all the correct pieces installed) and not disrupting airflow into the radiator.

And not driving like a lunatic.

 

[Justin_]

Good snow. Never thought all of the guides would be that important. I have another 98 sohc that recently had the rear timing chain guide go out that I can pull all of the parts from to transfer over.

I'm not sure that I still have the radiator drop brackets. I know I had them at one point but I'll have to look. Is there any way I can get 3-in radiator drop brackets from or anyone that could sell me some so that the fan shroud will match up?

 

[fast_dave]

The fan shroud directs the air flow, so you should try to get one. It's also a safety issue since the blades are exposed without it. Did you check the fan clutch to see if it's slipping? Do you know the temperature range of your thermostat?

^^^^^ Totally agree with BB on all 3 points.

From a person who lives in a hot/dry heat climate, I'd like to emphasize the following.
The 4 Liter Engine cooling systems are VERY fan clutch dependent.

Old School Fan Clutch Performance Test
Bring truck up to operating temperature.
Fold over an old section of 5/8" heater hose so it's about a foot long when doubled over.
With engine idling, and being aware of engine compartment surroundings, carefully insert the folded over hose in the path of the fan blades.
If the clutch is good, it will easily overcome the resistance of the heater hose, and act like it's a playing card on bicycle wheel spokes.
If the clutch is bad, the fan will stop spinning as the engine continues to idle.

Hope that helps -

 

[Justin_]

^^^^^ Totally agree with BB on all 3 points.

From a person who lives in a hot/dry heat climate, I'd like to emphasize the following.
The 4 Liter Engine cooling systems are VERY fan clutch dependent.

Old School Fan Clutch Performance Test
Bring truck up to operating temperature.
Fold over an old section of 5/8" heater hose so it's about a foot long when doubled over.
With engine idling, and being aware of engine compartment surroundings, carefully insert the folded over hose in the path of the fan blades.
If the clutch is good, it will easily overcome the resistance of the heater hose, and act like it's a playing card on bicycle wheel spokes.
If the clutch is bad, the fan will stop spinning as the engine continues to idle.

Hope that helps -

Ill check into that.

Thanks!

 

[fast_dave]

PS - Given what you wrote about your trip & temps, while you're trying to sort this all out, it would be a good idea to change your Motor Oil / Lifeblood Of Your Engine ASAP as it sure took a beating -

 

[donalds]

PS - Given what you wrote about your trip & temps, while you're trying to sort this all out, it would be a good idea to change your Motor Oil / Lifeblood Of Your Engine ASAP as it sure took a beating -

Great advice

 

[Justin_]

PS - Given what you wrote about your trip & temps, while you're trying to sort this all out, it would be a good idea to change your Motor Oil / Lifeblood Of Your Engine ASAP as it sure took a beating -

I did change it right before the trip. Always use motorcraft synthetic and filter, but still change it around 3/4k instead of 7/10k. Was going to replace it soon anyway. I do what I can to keep this thing alive

It's about to hit 100,000 miles on the odometer, but it did come with a switch that kills the speedo/odometer, so who knows what the actual miles are.
For that matter, is there much 100k maintenance to look at? Already recently replaced the tensioners/air filter/plugs, wires, coils/PCV valve/struts/wheel bearings/break pads/rotors/front diff serviced/rear diff was worked on just before I got it.

 

[CDW6212R]

At this age, check all four of the ball joints, the boots alone don't last 20 years. I've had to do those on the last two 98's I bought.

 

[donalds]

We need to open a
BJ boots R us. Lmao

 

[CDW6212R]

I have a new box of the polyurethane ones that do fit. I might have the other one too that is evidently a loose fitting part. My Mercury has the old style Moog LCA's, I think those I can save. They may have 10k miles on them, but the boots have fallen apart since I stopped driving it(just parked).

 

[donalds]

I just did my tie rod ends because of a broken boot

 

[C420sailor]

As mentioned, 100k is usually when the squeaking and groaning starts.

 

[Justin_]

At this age, check all four of the ball joints, the boots alone don't last 20 years. I've had to do those on the last two 98's I bought.

Recently with the rebuild I replaced the lower ball joints and the upper ball joints and arms along with the entire steering system so I think I'm good there.

A couple other more recent things I replaced the tie rods and sway bar bushings on the front and have the parts to do that on the rear as well. Most things on the truck that are rubber and get old have been replaced at this point. I'm just wondering if there's any other engine or transmission maintenance I should get up on.

 

[C420sailor]

Trans fluid changes every 30k will do wonders for longevity—especially in your climate

 

[Justin_]

Trans fluid changes every 30k will do wonders for longevity—especially in your climate

That's something I hear a lot about. I know it's good to change transmission fluid, but I also hear that if it's been a long time since it was last service it's good to not change transmission fluid. I did have a transmission cooler line break at one point and after repairing it had to add 4 qt or so to what I believe is a 13 qt system.

So what should I do there? Should I pull the pan get all of the oil out, clean it up, and put new oil in? Should I pull another gallon of oil or so out and replace it occasionally, say every other oil change? Or should I just leave it?

 

[C420sailor]

I’d change it. If you were at 250k, I’d say **** it and leave it.

The logic behind not changing it is that the trans is so worn that friction material floating in the fluid allows the frictions to keep from slipping. Your transmission shouldn’t be nearly that far gone at 100k.

A change in the 5R55E is never a true full change anyway. Some old always ends up mixed in with the new.

I’d drop the pan, change the filter, clean the magnet. Make sure you’ve got a good quality gasket. Install a drain plug if you’re so inclined. Pull the aux cooler and bring it to a shop to have it hot tanked and pressure tested. Reinstall everything. Install new hoses to the cooler. Now add fresh fluid to offset what you lost. Now use the cooling hose method that can be found on here to change the fluid. Some guys will only do another 7-8 quarts via this method after doing a pan drop. Others will do a full 12-13 for good measure. Yet others just go until then fluid coming out is clear and cherry red. Your call, but anything is better than nothing.