Radiator hose temp difference issue

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kingin

New member
Picked up a 02 sr5 4Runner 3.4 4wd 230k miles owner stated it had a bad headgasket overheating issue. Timing belt/water pump was done at 200k by maint sticker in engine bay.

After purchasing I went over car/engine etc, flushed radiator and cooling system (prestone super flush and garden hose t with t stat removed). I have now driven vehicle 500 plus miles in the past week no over heating what so ever. No coolant loss, no coolant in oil, no oil in coolant and no white smoke.

My issue is after vehicle is fully warmed up top radiator hose is hot and bottom is cool (changed t stat and also tested on stove prior to install) top radiator hose is also pressured can't squeeze it.

Again vehicle does not overheat or run hot have plenty of interior heat, vehicle runs great. Outside temps are about 60-75f daily.

Don't want to waste time on value cover gaskets tune up etc if engine is on its way out.

Thanks in advance
 
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Ok in my opinion (assuming the temp on the hot hose isnt over 200*) either the radiator is cooling really well or it isnt cooling very well(one of the 2 if the thermostat is good). How big is the difference? But if it is under normal temp and drives great I would leave it and just drive it, keeping up the maintenance.

Good luck
 
Top hose temp probably about 180f bottom hose about 70f. Felt the heater core hoses and both in and out are same temps. I'm puzzled besides this vehicle drives with no other issues.
 
Your normal. The rad cap has a vent valve. (It's the center thingie) the vent is normally loose to allow coolant to go between the rad and expansion tank. When hot water starts going through it it gets tight and seals. That's when the pressure builds. It's got a 13psi cap. So it's normal to hold pressure.
 
kingin said:
Top hose temp probably about 180f bottom hose about 70f. Felt the heater core hoses and both in and out are same temps. I'm puzzled besides this vehicle drives with no other issues.
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without a temp gun, and accurate readings, im going to guess and say its working correctly.

the coolant gets COOLER as it travels through the radiator. you would have a problem if the bottom of the rad was the same temperature, or warmer.
 
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Had the radiator tested for exhaust gases and it came back positive head gasket is bad. Now I need to find someone to do the engine swap for 500bucks labor or I'm gonna have to do it myself, I'm getting lazy.
 
kingin said:
Had the radiator tested for exhaust gases and it came back positive head gasket is bad. Now I need to find someone to do the engine swap for 500bucks labor or I'm gonna have to do it myself, I'm getting lazy.
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That's a pisser, But if your not overheating why change it out. It's normal for the hoses to have pressure.
 
kingin said:
My issue is after vehicle is fully warmed up top radiator hose is hot and bottom is cool (changed t stat and also tested on stove prior to install) top radiator hose is also pressured can't squeeze it.
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Think about this for a minute, and think about all you have said so far.


Coolant coming OUT of the engine is HOT, right?

Coolant going INTO the engine is supposed to be COOL, right?


The INPUT of the radiator is the TOP hose.

The OUTPUT is the BOTTOM hose.


The radiators job is to COOL the coolant.

Hence why the TOP hose is HOT, and the BOTTOM hose is COOL.




NOW, you said you did a flush and haven't had ANY overheating issues, right? NO oil in coolant, coolant in the oil, coolant loss.



If you've driven it 500 miles, and haven't noticed ANY of that stuff, I'm going to say you're fine.




NOW, if you're hellbent on it being a bad HG, just do the job yourself. It's not that hard to do.
 
Lol sorry didn't update completely.

Vehicle completely warmed up- Top hose of radiator has way too much pressure almost like a balloon effect and is always hot bottom hose normal pressure and always cold at least 100 degrees difference from top hose. Thought maybe I have a blockage in radiator replaced with a new one (if radiator wasn't issue my 96 4Runner is due for a rad replacement anyway). New radiator did not solve issue.

After reinstalling original radiator, I noticed tiny air bubbles being released with the cap off even after engine has been running for 45 mins+.

Also after driving vehicle for 2 days I do have loss of coolant probably a quart or 2 from radiator.

Vehicle does run and no overheating as of yet I drive it to work everyday lol.

Vehicle has 200k miles to resurface both heads local machine shop wants 250.00 total I'm assuming parts should be about 2-300, that puts me in the 500 bracket if all goes well. A replacement motor from local salvage yard with 130k cost 700 with 30 days warranty.

If replace headgasket it's a straight 500.
If I replace engine I should be able to sell off parts from the original motor (coil packs, mafs, throttle body, injectors, etc.) so cost without labor should be about the same.
 
I'd say get the 130 K mile motor, inspect the T-belt and components, get a new rear crank oil seal and slide it into your truck. Head job is easy but it should be done properly. I did my 4cylinder head gasket (yes, it was easy and a 4AFE Corolla motor) and after doing everything right, it still passed some compressed gas into the radiator. I had to remove the valve cover and cams to retorque the head bolts. Problem solved! Just my experience.
 
kingin said:
Lol sorry didn't update completely.

Vehicle completely warmed up- Top hose of radiator has way too much pressure almost like a balloon effect and is always hot bottom hose normal pressure and always cold at least 100 degrees difference from top hose. Thought maybe I have a blockage in radiator replaced with a new one (if radiator wasn't issue my 96 4Runner is due for a rad replacement anyway). New radiator did not solve issue.

After reinstalling original radiator, I noticed tiny air bubbles being released with the cap off even after engine has been running for 45 mins+.

Also after driving vehicle for 2 days I do have loss of coolant probably a quart or 2 from radiator.

Vehicle does run and no overheating as of yet I drive it to work everyday lol.

Vehicle has 200k miles to resurface both heads local machine shop wants 250.00 total I'm assuming parts should be about 2-300, that puts me in the 500 bracket if all goes well. A replacement motor from local salvage yard with 130k cost 700 with 30 days warranty.

If replace headgasket it's a straight 500.
If I replace engine I should be able to sell off parts from the original motor (coil packs, mafs, throttle body, injectors, etc.) so cost without labor should be about the same.
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im not really sure whats going on, but that makes absolutely no sense. its a sealed pressurized system. all the components in the system should see the same pressure. unless of course there is a blockage somewhere....


perhaps the upper hose is just weak, and needs replaced.
 
That's exactly what I was thinking, I'm using my 96 4Runner 3.4 as comparison and both hoses are similar temps and I can definitely squeeze the top hose after vehicle has been warmed up on my 96 4Runner.

Local shop mechanics theory is- previous owner- radiator went bad overheated caused a slight headgasket leak, new radiator was installed noticed overheating issue added a stop leak additive and here we are.

So have a bad head gasket which is temporarily band aided with stop leak, and a blockage somewhere due to adding stop leak hahahha. Mechanic has a good theory I think.
It's pretty odd since vehicle dosnt overheat or run hot as per interior temp gauge.
 
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