Head gasket replacement

[mtltemplar]

My truck has been having overheating issues off and on for a couple years. When it pegged the gauge a couple times I took it to the shop and they did a coolant flush and found a bunch of air in there. After that it didn't overheat again for the last 9 months until I started using the heater again and now it's right back to regularly overheating after just 10 minutes of standard driving. Now they're saying it's the head gaskets...

Being a shade tree mechanic myself, I'm wondering how hard it would be for me to replace those myself? I've rebuilt the manual tranny in my 3000gt vr4, and numerous other things with that car (turbos, engine pulls like 5 times, etc.) so I've got reasonably decent mechanical skills and tools... Has anyone on here tackled it themselves? Or something I really shouldn't try?

Thanks

 

[VPRPWRD]

It's really not that hard, it is a push rod v engine with 2 extra cylinders. I will help you with anything you need.

 

[VENOMOUS1 RACING]

Not terrible but not for the faint of heart either. I can get you upgraded head gaskets as well as new head bolts. Have heads checked while off. New set of springs wouldn't hurt either.

 

[rottenronnie]

My truck has been having overheating issues off and on for a couple years. When it pegged the gauge a couple times I took it to the shop and they did a coolant flush and found a bunch of air in there. After that it didn't overheat again for the last 9 months until I started using the heater again and now it's right back to regularly overheating after just 10 minutes of standard driving. Now they're saying it's the head gaskets...

Being a shade tree mechanic myself, I'm wondering how hard it would be for me to replace those myself? I've rebuilt the manual tranny in my 3000gt vr4, and numerous other things with that car (turbos, engine pulls like 5 times, etc.) so I've got reasonably decent mechanical skills and tools... Has anyone on here tackled it themselves? Or something I really shouldn't try?

Thanks

You can easily check the operation of your hydraulic fan system, as follows:

Take off your rad cap ( I'll explain later)

Shut off your A/C.

Open the bleeder valve on top of the thermostat housing.

When the engine is starting to warm up, disconnect the electrical fitting on top of the thermostat housing. In a short time, it should sent your fan into HIGH speed. It will also pin your temp gauge and trip a check engine light (both are temporary conditions). If your fan is roaring away, all is good there and you can hook up the electrical.

Let the engine warm up and when no more air is coming out of the bleeder (close it). Add fluid if required.

Now, have a look in your radiator. If there are bubbles coming out, it could be a head gasket issue.

I have had a thermostat go bad and it was an intermittent overheating issue.

The head bolts are good for (3) pulls according to Chrysler people in the know. I've always replaced them after that. The factory install when your engine was built counts as one.

Do NOT oil the head bolts; and in fact, blow out the block holes or use a rag if you can to get them as dry as possible, if you end up having to pull the heads.

Good luck.

 

[Slitherbeast]

Best to identify exactly why it is over heating instead of replacing the head gaskets. they seal pretty darn good! the engine will break pistons before the headgasket lets go! Like Ronnie says make sure the fan works , and there is no air in the system. seems like the problem arises from using the heater. maybe you have a heatercore leak?

 

[NukeGM/Ford]

You can easily check the operation of your hydraulic fan system, as follows:

Take off your rad cap ( I'll explain later)

Shut off your A/C.

Open the bleeder valve on top of the thermostat housing.

When the engine is starting to warm up, disconnect the electrical fitting on top of the thermostat housing. In a short time, it should sent your fan into HIGH speed. It will also pin your temp gauge and trip a check engine light (both are temporary conditions). If your fan is roaring away, all is good there and you can hook up the electrical.

Let the engine warm up and when no more air is coming out of the bleeder (close it). Add fluid if required.

Now, have a look in your radiator. If there are bubbles coming out, it could be a head gasket issue.

I have had a thermostat go bad and it was an intermittent overheating issue.

The head bolts are good for (3) pulls according to Chrysler people in the know. I've always replaced them after that. The factory install when your engine was built counts as one.

Do NOT oil the head bolts; and in fact, blow out the block holes or use a rag if you can to get them as dry as possible, if you end up having to pull the heads.

Good luck.

I wondered what that bleeder valve was for, thanks

 

[10-1=9]

I wondered what that bleeder valve was for, thanks

Every engine should have that cooling system bleeder valve.

 

[NukeGM/Ford]

Every engine should have that cooling system bleeder valve.

Do you mean as in, it's a good thing they all should have, or, why haven't I seen it before?

 

[10-1=9]

Do you mean as in, it's a good thing they all should have, or, why haven't I seen it before?

When filling any cooling system an air pocket usually gets trapped behind the thermostat. The water pump is really an impeller and will not move air (an other issue) So what you end up with (after starting the engine) is a steam pocket trapped in the block. Hot air will not open the thermostat only hot liquid will. The water pump is no help moving the hot air. The bleeder lets you vent the air out just like in a brake or hydraulic clutch system. They usually only add bleeder fittings to systems with high spots. I suspect a fitting was really needed for the car not the truck.

 

[JTS VENOM PERFORMANCE]

just go to advance they rent a radiator pressure tester, they will let you for free, pressure up the system if it leaks down.......ya got a leak, figure out where that's from, fix.
more than likely after burning hot like that a couple times, yes, head gaskets. but easy and free to find out, pretty simple,

 

[10-1=9]

just go to advance they rent a radiator pressure tester, they will let you for free, pressure up the system if it leaks down.......ya got a leak, figure out where that's from, fix.
more than likely after burning hot like that a couple times, yes, head gaskets. but easy and free to find out, pretty simple,

You can also check if pressure is building up in the system that's not from the fluid heating up. With the system full install the pressure tester but don't pump it up. Then start the engine & watch the gauge. If it immediately starts building pressure you got a compression leak. This would indicate a blown gasket or cracked head.
Back when tail pipe Emission testers were common in PA we would pass the probe over the rad neck or overflow bottle. If you got any hydrocarbon reading the head gasket was most likely blown.

 

[mtltemplar]

Finally got some time off work to test stuff out:

Uncapped the rad, unscrewed the bleeder valve and a small, and I mean *small* amount of air came out, nothing more, just fluid after that. Ran the truck, disconnected the electrical sensor when it started to warm up, fan kicked into high almost immediately, needle pegged, CEL tripped. Reconnected it. (Interesting side note, that is precisely what's been happening and about as quickly with the gauge rising and then falling when plugged back in, wonder if it's not really overheating and it's just a sensor going bad - anyone had that happen before?)

Let the engine keep warming up, and since it was just straight fluid coming out the bleeder, I went ahead and closed it. Checked the reservoir and it was about 1/3 up from min, so I added a little distilled water to get it to about half way. Upper hose was hot to the touch, temp was around 205 or so, lower hose was warm but not hot, looked into the rad and the fluid level was maybe 1/4 of the way up from the bottom... That said, there were no visible bubbles in the fluid, but it seems to me that that is WAY too low, shouldn't it be nearly, if not completely, full?

I let it cool down completely (overnight) and tried it again just now today, same process as above, same exact results as above, except this time the needle edged up to about 220/225 and stayed there. After it was at 200 I even capped it, drove it up the road a ways (stomping on it some to get it good and hot) and back home, parked it and felt the cap and it was still practically cold to the touch, I was able to slowly remove it without any fluid coming out, just the expected air from depressurizing the system... After that is when it got up to 220/225 and stayed there.

All that said, maybe too soon to rule out head gasket? Possible radiator plug (but then why is the lower hose warming up too)? Thermostat on the wack? Sensor going bad? Too many variables, wish the shops knew what they were doing with these things, feel like I can't trust any of them...

 

[johnthegoalie]

So the shop "fixes" it and its all good until the heater gets turned on which is a good indication they probably didn't bleed it completely...

Now, did you ever pressure test? Instead of throwing shit at the wall and guessing, why not take a step back. Figure it's a 10 year old truck and there isn't much to the cooling system. After ruling out any leaks, why not drain it completely, flush out the block and rad, put new hoses and a thermostat, refill and bleed correctly.

If you are going to bring it somewhere, remember there are a lot of hacks out there. Find a good viper mechanic (a dedicated srt dealer will have at least one)that will fix it right the first time. A good viper mechanic is like a good tattoo artist... Hard to find but worth the effort to locate...

 

[ZCx]

the heater in our trucks & most late model stuff, the heater is "ON" all the time. its the blend doors that handle the temps.

 

[VENOMOUS1 RACING]

Thermostat

 

[10-1=9]

the heater in our trucks & most late model stuff, the heater is "ON" all the time. its the blend doors that handle the temps.

I think you mean that hot coolant circulates through the inside heater core anytime the engine is running. The heater core (hot) & evaporator core (cold) are mounted in the same box. It's up to the blend air door to determine the temperature of air coming out the vents.
Some cooling systems are designed with a valve in the heater hoses. When max AC is on it keeps the hot coolant out of the passanger compartment.

 

[mtltemplar]

So... finally rustled up the $217 it took to 'rent' the cooling system pressure tester kit from Advance. With the system off and cold, installed the pressure tester, pressurized to 16 PSI (what's on the rad cap) and left it for a couple minutes with 0 pressure loss. Then I released the pressure back to 0, and turned the truck on and let it run about 5 minutes with 0 increase in pressure.

Safe to say not the head gaskets then - between that last test and not seeing bubbles in the system? Also safe to say I should start with thermostat and coolant temp sensor (since they're about $45 together from Napa) and then refilling and bleeding properly according to the service manual and see if the issue is resolved?

 

[10-1=9]

So... finally rustled up the $217 it took to 'rent' the cooling system pressure tester kit from Advance.

I guess it was rent to own. Lol

With the system off and cold, installed the pressure tester, pressurized to 16 PSI (what's on the rad cap) and left it for a couple minutes with 0 pressure loss. Then I released the pressure back to 0, and turned the truck on and let it run about 5 minutes with 0 increase in pressure.

Did you also pressure test the cap?
You could also have left it on longer until the system heated up.

Safe to say not the head gaskets then - between that last test and not seeing bubbles in the system? Also safe to say I should start with thermostat and coolant temp sensor (since they're about $45 together from Napa) and then refilling and bleeding properly according to the service manual and see if the issue is resolved?

That would be a good start. Although it's not common with our trucks I have seen a head gasket leak intermittently before.

 

[mtltemplar]

That would suck if it's just an intermittent issue, but at the same time it was fine all year until I turned on the heater again for the first time, so one can always hope it's something simpler...

 

[mtltemplar]

Do I replaced the thermostat, temp sensor and auto tensioner/belt. Getting ready to start bleeding when I notice it seems the belt has jumped one rib up onto the edge of the P/S pulley, but only on that one, the rest of them it's in the right place... With the new tensioner, that shouldn't be happening, right? All the pulleys (minus the crank pulley obviously) spin easy enough by hand, none of them seem stuck. WTH? Stopped cause I didn't want to run it like that for long, I did reuse the old belt which has maybe 4 months usage so far, so it should be new 'enough' to use, right? It's not cause of the angle of the driveway I'm idling it at, is it? If the tension is right it shouldn't matter there should be enough pressure on it to keep it on the grooves I'd imagine.