heating issue

[explorer98]

I live in Wyoming and went to Colorado. Ive got an 98 explorer with a 5.0 that I rebuilt and has about 4000 miles on it. It ran fine their and at a traffic light it started to run rough. When I gave it gas it would back fire and had no power. I thought maybe it was a plug wire but they were all good. I got it back on the interstate and it would hardly go. Finally got it up to speed and it seemed out until the first hill and it down shifted and was back firing. Just before the Wyoming boarder it died and the radiator blew up. Any suggestions

 

[Spott]

Don't try to get on the interstate when your vehicle is backfiring and has no power?

Sorry, had to say it.

Honestly, I'd initially suspect timing issues...although, that doesn't explain the cooling problems.

 

[black_demon69]

check t stat to see if stuck closed
check rad cap
check cooling system for leaks
radiator plugged possibly?

back firing could just be detonation due to over heating..

 

[Kowboy]

Thermostat stuck definitely, and since it was rebuilt recently, I'd look for sealant / gasket material in the inlet side of the radiator. Trash from the rebuild could have collected there and clogged it. Is your temperature gauge working?

 

[RonD]

Yes what was the temp gauge showing while you were losing power?


Could be you were losing fuel pressure, should be 65psi on '98.
Lower pressure causes Lean mix which has no power and burns Very Hot, causing overheating.
Did you notice any pinging?

 

[explorer98]

The temp gauge didn't move from its normal spot stayed in the middle, but that doesn't mean it was working wright. Didn't notice any pinging just when you would give it any gas it would chug and back fire.

 

[RonD]

I would compression test at least 3 cylinders should be above 150psi, just to take timing chain off the table.

My guess at this point would be head gasket failure, it would explain the rough running(coolant in cylinder) and then overheating in the end, loss of coolant and too much pressure in cooling system from 700+psi during combustion.

If you can seal the cooling system back up(not sure what radiator blew entails, lol) you can put a latex glove over the rad cap opening, seal it with rubber band, and crank the engine(unhook the coils)
If glove bounces then you have a head gasket leak, assuming sealed cooling system, it doesn't need coolant in it, just needs all hose tight for this test.

If glove bounces then remove 1 spark plug at a time and crank engine, when glove stops moving the last spark plug removed was from the leaking cylinder, re-install plug to confirm.
I had 2 leaks on a 4.0l once, glove didn't bounce as much when one cylinder was IDed, then stopped bouncing when seconded cylinder was IDed.
My guess on that one, was that head gasket failed and overheating caused head to crack on the other cylinder, but could have been the other way around, lol

 

[explorer98]

Sorry when I say the radiator blew up, it blew the side of it out at the top hose. A hose didn't blow the plastic part of it did. The hose was still connected to the part that blew off. I checked the oil and it looks fine no coolant in it so maybe that's a plus. I guess I should tell you I don't have the clutch fan on it I put two electric fans on. My guess is that I should go back to the clutch fan.

 

[RonD]

No, electric fans are better, if hooked up of course
If you are worried about it you can install a small led light inside that will come on when fans do.

What was the PSI rating on the rad cap?

Coolant in the oil means head gasket had a very large failure.
Most common head gasket failure is cylinder to the cooling system since each cylinder is surrounded by coolant passage holes thru the gasket, so when the metal cylinder ring on the head gasket fails a coolant passage is usually where the pressure is relieved.
If enough pressure builds up then gasket failure spreads farther out and encounters oil passage or drain.

With broken rad you won't be able to do the Glove Test.

 

[explorer98]

The rad cap was rated for 16lbs. I forgot I used the stock v6 radiator when I did my engine swap, but I have one for a v8 on the way.

 

[explorer98]

Well I found that the passenger side head gasket is blown, but I have a question can you just change the one or would it be better to change both of them?

 

[black_demon69]

Well I found that the passenger side head gasket is blown, but I have a question can you just change the one or would it be better to change both of them?

IMO change both because you already have it all apart..