3.0 overheating at highway speeds

[Kane]

Hi guys, long time lurker-first time poster here.
I recently just picked up my buddies old 1998 3.0 4x4 ranger. When he originally bought the truck it needed a head gasket, I installed brand new heads for him and its ran fine for the last 2k miles.
Now it has a little bit of a misfire here and there, It smooths out in the higher rpms. But, while cruising 60-70mph the heat climbs to just below the red tick on the dash, doesnt actually make it past the white (safe) range.
Feels like it is really lacking on power as well.
I'm pretty confident its not another head gasket, did the glove test, looked alright. My next thought it plugged cat?
I'm planning on dropping the cat tonight, along with doing the fuel filter. (I should add, buddy changed his passenger side control arm, truck started acting up after that, is there anything un-plugable around there?)
Long story short, Truck has new heads with 2k miles. New plugs with new plugs and wires (Doing coil pack tonight aswell, along with cat).



Thanks in advance!

 

[Eddo Rogue]

The 3.0 lacks power. It helps when paired with a manual trans, so you rev the piss out of it. It is designed for upper rpm range.

Dont pull the cats, it will just make it worse. Trace that misfire, could be a few things.

As far the overheating, I would check the Fan clutch, waterpump, and thermostat for starters.

 

[Kane]

The 3.0 lacks power. It helps when paired with a manual trans, so you rev the piss out of it. It is designed for upper rpm range.

Dont pull the cats, it will just make it worse. Trace that misfire, could be a few things.

As far the overheating, I would check the Fan clutch, waterpump, and thermostat for starters.

Fan clutch is always engaged, was thinking about pulling my fan clutch and swapping in an electric fan.
I have a new thermostat I can swap in, I'll do that thanks! as for the water pump, the truck can idle all day and not overheat, I'm thinking my waterpump is okay.
I'm not necessarily planning on removing my cat or cats? If its looking plugged, I planned on smashing it out with a piece of rebar.
If I decide to remove the cats in the future, I will be replacing it with a proper test pipe.
My roommate had this same truck except it was auto, seemed to have a ton more power.

 

[cbxer55]

The 3.0 lacks power. It helps when paired with a manual trans, so you rev the piss out of it. It is designed for upper rpm range.

Dont pull the cats, it will just make it worse. Trace that misfire, could be a few things.

As far the overheating, I would check the Fan clutch, waterpump, and thermostat for starters.

4.10 gears in the axle are also a yuge help. Mine is a 98 3.0 automatic, and it doesn't lack power at all. Since putting in the 4.10's, it accelerates better and actually has a faster top end than it did with the 3.73.s. My automatic also has a shift kit installed, and you can definitely tell when it shifts gears. BAM! Modified exhaust with no muffler, tips in front of passenger wheel. MAC cai with three sources of cold air intake. Tuning chip on the computer that changes the fuel trims, advances the timing more, and raises the shift points. I love it. It doesn't lack power at all once moving. Yeah, when first starting off, it kind of bogs a bit. Once the rpms are up, get out of my way!

 

[stmitch]

Check to make sure that there's no junk trapped between the AC condenser and the radiator that could be limiting air flow through the radiator.

 

[ekrampitzjr]

Elephant in the room: the radiator.

If some "stop-leak" junk such as Bar's Leaks has ever been used, which is likely with a past head gasket repair, then the radiator is probably clogged and causing the overheating. Since the problem shows up at higher speeds, I think this is going to be the problem. The engine and cooling system are under higher loads on the highway, compared with idling and low-speed driving.

Racing Beat, the outfit that made performance parts for rotary Mazdas, said emphatically NEVER to use such a product in those cars as it would clog the radiator and cause engine overheating and failure. I think the same applies in every vehicle.

If it turns out the radiator is clogged, you should also check the heater core. It might be possible to back-flush that to get the stop-leak gunk out and salvage the core. However, if Bar's Leaks was used in the system, it might have been because of a heater core leak and not a radiator leak.

Before I bought my 2011, I walked away from another (2009, I think) Ranger because the owner had had a heater-core leak and had used Bar's Leaks. The truck also had the SOHC 4.0. No way. Talk about trouble brewing.

 

[Eddo Rogue]

All sound advice. Bear in mind My point of view is from Commiefornia where tampering with cats is a major no no. Political trauma.

 

[ekrampitzjr]

All sound advice. Bear in mind My point of view is from Commiefornia where tampering with cats is a major no no. Political trauma.

Virginia does a visual to make sure the cats are there as part of the safety inspection, and certain jurisdictions in Northern Virginia do an emissions check. But even if I could be 100% sure of getting away with removing cats on a street vehicle, I wouldn't do it. Not only were today's cars and trucks designed with them, but I like clean air too.

 

[Kane]

Check to make sure that there's no junk trapped between the AC condenser and the radiator that could be limiting air flow through the radiator.

This truck didn't come equipped with A/C. Great suggestion though, Thanks!

Elephant in the room: the radiator.

If some "stop-leak" junk such as Bar's Leaks has ever been used, which is likely with a past head gasket repair, then the radiator is probably clogged and causing the overheating. Since the problem shows up at higher speeds, I think this is going to be the problem. The engine and cooling system are under higher loads on the highway, compared with idling and low-speed driving.

Racing Beat, the outfit that made performance parts for rotary Mazdas, said emphatically NEVER to use such a product in those cars as it would clog the radiator and cause engine overheating and failure. I think the same applies in every vehicle.

If it turns out the radiator is clogged, you should also check the heater core. It might be possible to back-flush that to get the stop-leak gunk out and salvage the core. However, if Bar's Leaks was used in the system, it might have been because of a heater core leak and not a radiator leak.

Before I bought my 2011, I walked away from another (2009, I think) Ranger because the owner had had a heater-core leak and had used Bar's Leaks. The truck also had the SOHC 4.0. No way. Talk about trouble brewing.

Great info, Thanks. I will try flushing both my radiator and heatercore!


Update:
I installed a new coil pack lastnight, seems to have fixed my misfire issue, aftermarket coil pack mounts backwards from OE, so keep that in mind if you replace with aftermarket!
It did start heating up on the freeway, but It took twice a long as it did before. Going to drive it through the week and do the radiator flush this weekend along with fuel filter and cat inspection. Wish I had a bigger garage!

 

[Burnsy]

This truck didn't come equipped with A/C. Great suggestion though, Thanks!







Great info, Thanks. I will try flushing both my radiator and heatercore!


Update:
I installed a new coil pack lastnight, seems to have fixed my misfire issue, aftermarket coil pack mounts backwards from OE, so keep that in mind if you replace with aftermarket!
It did start heating up on the freeway, but It took twice a long as it did before. Going to drive it through the week and do the radiator flush this weekend along with fuel filter and cat inspection. Wish I had a bigger garage!

Let us know if you resolve it, do a final comment please

 

[superj]

On the highway heating is radiator, as noted above. Pull the radiator and clean it flush the system. You can pressure test everything too but i would plan on just replacing the radiator from the beginning and anything else as you work through it amd find it needs it

 

[pjtoledo]

the 3.0 has drains in the block. you can get a lot of crud out from them.