New head gasket, now truck overheats

Old stat/improper install of stat/wrong temp stat/, Air in system (I have never encountered air lock in coolant system in over 40 years ) but for 'yota's apparently it exist.

Haven't heard any mention of soft hoses...

 

Soft hoses?

To the OP: Park on an incline, turn on car and heater, fill radiator, rev it a few times, then put the cap on and leave it alone.

Remember this thing has been siting for 4 years. With all this screwing around, hes just getting closer to having to pull the heads and starting over. Any buildup is from years of sediment and rust suddenly getting pulled through the system.

Also getting closer to the point of just setting the thing on fire and telling the insurance company some inner city kids did it.

 

Yes, a/c condenser, dont mess with that either. Either auto or manual radiator will fit, you just can get a manual radiator without the lower a/t cooler if yours is m/t. I doubt it needs replacing, find a radiator shop to have it checked, but i dont think thats it.

The fan clutch is there to keep the fan at a somewhat regular RPM independent of the engine RPM. That thing would explode if it went from 1000 to 5000RPM over and over again. If its working, its working.

How does the exhaust look? Smoke or steam present?

Still waiting to hear of OP's records regarding the heads being straightened.

 

This place is great. I'm pretty thrilled with all the feedback. I'll try to address all the questions in this post.

The "mechanic" who did the work was a friend who I thought was competent as they had rebuilt the motor on a s10 and used that truck as his daily driver for years in the city. I had to leave town and he had just moved to town and was looking for work. So I bought the FSM and gave him the HG job. He felt pretty shitty about the result and didn't want to make anymore mistakes so we called it even. I believe using what little sense we had the decision was mutual to not surface and pressure check the heads. Based on a visual assessment we felt the head gasket failed on the passengers side forward corner. In that area directly beneath the seam between the heads and block we observed a coolant leak trail running from the head gasket. Based on that and that alone we decided to do the HG job. I assumed it was not the water pump at the time because we had just replaced that when we replaced the timing belt months earlier. Obviously we are idiots and more thought could have been put into it, but it is what it is. Moving on.

When the repairs were made I was out of town and I was a little concerned they might order and sell the wrong headgasket at the local parts store (napa). So I reiterated multiple times to check and double check while sober. So don't think they sold him the wrong head gasket. My friend mechanic also told me when it was installed they made sure that none of the ports were covered and everything lined up.

The hoses on the radiator have been observed during an overheating event. When the truck starts to rise above normal operating temps (8:30 on a clock) we looked at the hoses. The bottom hose is a rigid ribbed thing that looks like a universal hose and the way it's routed it does have a slight kink at the top (it's more like a corner). But it's small I and can't see it restricting the flow much. The top hose is fairly soft and when overheating it does appear slightly squashed in the middle but again not enough to restrict flow in my opinion. Neither hose has sucked flat.

Truck is on a slight incline. We drained and changed the thermostat then filled with truck off. Started and ran with heater on and radiator cap off. We idled till the coolant level dropped (thermostat opens?). Topped off, capped the radiator, engines idles for ~20min holding at normal operating temp (8:30) and then temp gradually starts to rise. There is no smoke or steam coming from exhaust while this is happening except for the very small amount that comes out when starting with the engine cold like always.

I say we because I have another friend who's dad used to run a radiator repair shop. He is retired now but we had him on the phone talking about what we were seeing. He brought up an issue with the bubbles we saw in the radiator neck. He is saying that any bubbles at all during refill means HG issues. I mentioned this earlier and no one really hit on it so i'll bring it up again. I tried burping the truck again with the rad cap off and heater on, truck parked on a slight incline. The engine warmed to regular operating temps and I observed the coolant level in the radiator neck "bobbing" up and down with some spillage from overflow. After idling for 15 min and not overheating, i noticed the occasional bubble surfacing every few minutes. when 20 min had passed and the truck still didn't over heat I decided to try turning the heater off, that's when the coolant started erupting from the radiator (can someone please tell me why this is happening?). I then turned the heater on and topped off the radiator and the erupting stopped, temps were stable at 8:30 on the gauge through all of this. The temps remain good, until I put the radiator cap back on then they start to climb, eventually. Maybe the temperature will climb eventually without the rad cap on but I haven't seen it do this yet and we've waited a long time. What do the bubbles indicate?

Sorry for the long post, but you all seem interested in how this turns out and I really appreciate your opinions so I wanted to communicate as much as possible. I'm in this for the long haul, but once I get to a certain point it goes to a competent mechanic who has a shop and reputable business here in town. I can change radiators, fan clutch, fluid, caps, etc. and those things probably need replacing anyway so i really don't mind.

Thanks again.

And I will purchase a new aisin fan clutch.

 

I would replace both rad hoses with oems from the dealer. they both sound like they have minor issues so get rid of them.

install a flush valve up top near the heater hose outlet to be certain you burp all the air out of the system. this eliminates any questions of trapped air in the system. this is what they look like: http://www.ebay.com/itm/47152-Dorma...ash=item3ab27bc35c:g:hXsAAOxyYSdTD~jq&vxp=mtr

at this point I would think its likely the thermostat is just bad or not working right so go get a new oem thermostat from the dealer to eliminate that as a possible cause. I have read a few online posts about aftermarket thermostats causing overheating problems.

also a "guess" is it "might" be related to if the radiator fan isn't moving enough air if the fan clutch is bad. can you feel resistance in it when you try to turn it? it should stop right away and shouldn't be able to continue to spin after you try to spin it

 

Doesn't the fan clutch "engage" when the temp in the engine compartment reach a certain level? If it's failing to engage could that be part of my issue?

The thermostat we installed (thermostat #2 since HG job) was a Tama made in japan. Not oem but close enough? We also tested it and it opened at ~84C but didn't measure how much it opened.

 

Fan clutch resistance is very little, I can spin it easily cold but it won't continue to spin. Also, I don't have much to compare it to, I've never spun a fresh fan clutch.

Edit: I can hear the fan clutch at start up when it's cold, it roars for half a minute then quiets down. But I never hear it roaring while it's hot

When the engine is running hot and I turn it off I can watch the fan clutch spin for several seconds.

 

only go with oem dealer thermostat, trust me on this. weather its really a problem or not, only the oem stats seam to work correctly in these trucks

I must have read more then 2 dozen forum posts where it turned out the aftermarket stats were the problem all along

 

determining exactly when a fan clutch is bad is something I still don't understand where to draw the line where you say its definitely bad or not. I was told you are supposed to replace them every 75k miles or so but then most people NEVER replace them and don't have problems.

im told they spin fast on start up just until the oil warms up and then as you drive, when the temp coil gets hot telling it more cooling is needed, its "supposed" to tighten up on the adjuster to make it spin faster for more cooling but I still haven't read of a way to test this.

so far the only answer I ever got was when the engine is cold, spin the fan and it shouldn't spin on its own

 

Brb - purchasing oem thermostat and installing with fingers crossed.

 

"To the OP: Park on an incline, turn on car and heater, fill radiator, rev it a few times, then put the cap on and leave it alone."

Did this

"only go with oem dealer thermostat, trust me on this. weather its really a problem or not, only the oem stats seam to work correctly in these trucks

I must have read more then 2 dozen forum posts where it turned out the aftermarket stats were the problem all along".

And this

Now when idling for twenty five minutes the truck does not overheat. The temp gauge hung at 8:30 and slowly worked its way up to 9:30 after >20 min of idling. The whole time it kind of fluctuated, but only very very slightly.

I suppose the next step is to get it tagged and take it out on the highway. I'm still replacing the fan clutch and hoses but wanted to just try the oem thermostat replacement to check for a difference. Thanks for your time and thoughts. If there is anything thing else you all think I should do for the overheating issue I would be happy to hear it. Problem solved? Maybe, maybe not.

 

Keakar, you surprise me stating that. Any quality thermostat will be fine, i use Stant Xact thermostats on mine. Yes, with the jiggler at 12 o'clock. The pic i posted on the second page of this thread is from the Amazon page for the thermostat ive ordered twice for my truck. Once when i first bought it 4 years ago, second when i replaced the radiator about 6 months ago.

I really think there is too much shit swirling in this thread. OP needs to stop throwing money and parts at items hes not sure are even bad. I still stand by that a total rebuild in going to be in his future.








And for the third time.... do you have the invoices from the shop where the heads were machined/straightened?

 

No, we never had the heads surfaced and pressure checked. There is no invoice, this job was a HG swap in a barn.

I don't mind replacing components in an attempt to troubleshoot. If I have to pay to install new head gaskets so be it. I decided that before it goes to the shop for the HG job I get to take a crack at it first.

 

did you put in the radiator flushing tee? it makes life so much easier to purge all the air out of the engine.

 

No, I didn't install the t but I want to.

 

any auto store will have them

 

Engine overheats while driving 55mph, no hills.

 

That is why this is leaking and overheating.

 

at this point im leaning towards a clogged up radiator, its the only thing that makes sense to explain all your issues and everything you did so far with no improvement. a bunch of crap may have come loose during the head job and clogged up the radiator as soon as water started circulating.

take your radiator off and leave the cap and the hoses on it then put a pvc fitting with 3/4" connector to hook a water hose to it. then turn on the water and flush in the opposite direction of normal flow until nothing but clean ater comes out then flush it in the other direction and do this a few times until its totally clean.

maybe something like this: http://www.homedepot.com/p/Charlott...-FPT-Reducer-Bushing-PVC021080800HD/203811581
wrap tape around it until the hose clamps onto it without leaking

after you do this, remove the thermostat and flush out the engine block as well in both directions just like you did the radiator so your whole cooling system is flushed out. even if this doesn't solve the problem its a good thing to do to your truck and it doesn't cost anything to do this but time.