Blown head gasket? Best options?

[beachcruiser]

Thanks in advance for any advice and input... Here goes:
My hundy with 250k miles had a sound under the dash that sounded like a mouse had worked it's way into blower and was trying to dig/claw its way out... I resolved to break down blower the best evening. Apparently not.
Wife was driving it down the interstate when she got an extended hiss coming from engine compartment, and got off highway as quickly as possible, while starting to blow white smoke out from under hood.
Temp was redlining and she shut it down Asap, and after getting it hauled to garage, we checked and it appeared the T in the coolant lines at the firewall had split. We repaired the T and refilled coolant to check for other potential issues/causes or effects of the coolant loss and ran into this conundrum: temps spiked after a minute and checking heater in cabin wouldn't yield any heat, and had the following symptoms:
- hose from radiator is scalding hot but return isn't/can be held. Same for lines into and out of heater core. This is where I ran out of ideas...
-water pump definitely is demonstrating a leak as well now (which wasn't there before/didn't notice before). This could have caused overheat OR been a result of over pressure from item below?
- my MECH did a test on coolant where a dye that detects fluorocarbon is introduced which tested positive, which he said is a pretty solid indicator of a blown HG.

So here's where I'm going... they recommend at this mileage to put in a new engine. I could do HG, water pump, timing belt, idler etc but am I potentially just putting a lot of work into something that could need bottom end work soon as well?

Of course I'm open to all options....
-I could swap in another 100 engine.
- are diesel conversions even practical or feasible?
- ideas?

Thanks in advance... the minute this literally blew up the first thing I knew was that the 'Mud forum would be where I needed to go. Thanks fellas.

 

[Sandroad]

First, it sounds like you have a stuck thermostat and that may have been the cause of the overheating, broken T's, and leaking water pump. Or the T's could have broken and the resultant coolant loss did in the thermostat and pump. If it was mine, I would replace the thermostat and coolant, then do another test for head gasket failure. Someone who knows which test is best will chime in here, but I wouldn't give up on that engine until you know for sure a HG is blown. If it is, a used engine (no need for new) is a possible solution. If it isn't, just do the T-belt/pump change service and be on your way! And no, a diesel conversion is not practical or feasible!

 

[nissanh]

Toyota engines are strong. If you did not have any bottom end issues, you should be fine.

If you open the piston cylinders you will be amazed to see how it looks like. I did the HG in my car (Toyota) at 240 K miles (all due to my fault) and was stunned to see the cylinder bore hones still! There were NO groves cut on the cylinder bore by the moving piston rings. I did the complete HG job and man, it runs like new.

Make sure to get OEM HG. Get a complete HG job (valve guids, valve seals etc) from a reputed machine shop.

 

[DirtDawg]

I'm with @Sandroad on this one. Head gasket failure is not common on these engines unless they were extremely overheated and that does not sound like the case. Replace the t-stat and see if that fixes it.

We're the heater Ts ever replaced?

 

[beachcruiser]

Thanks for the .02.
I'll give it a shot with the tstat and go from there. The lack of circulation to and from the radiator and heater core could just be water pump? I'm wondering if heat could have jacked up the impeller....

To be honest I've got to find out more about the flourocarbon test they did and how it empirically shows HG issues.

 

[beachcruiser]

I was doing some digging since my Mech is out for the night about the test he performed and its "hydrocarbons," not fluorocarbons. I found this write up which was almost identical to what he described down to the test liquid switching from blue to yellow.

So theoretically saying there is the presence of combustion gases in the coolant, is there any practical way these two could have gotten mixed without it being a HG issue?

Blown Head Gasket Diagnostic - Tricks Of The Trade - Import Tuner Magazine

 

[beachcruiser]

I'm with @Sandroad on this one. Head gasket failure is not common on these engines unless they were extremely overheated and that does not sound like the case. Replace the t-stat and see if that fixes it.

We're the heater Ts ever replaced?

I don't think the heater Ts ever were replaced by the PO (or me for that matter).

 

[nissanh]

The hydrocarbon is a common name for any crude oil derived fuel. Coolant is just ethylene glycol and water. Ethylene glycol is not a hydrocarbon. So if you find a sign of hydrocarbon in coolant then you can say the head gasket is leaking into the coolant syatem.

Here is another way to find out.
DO IT ONLY WHEN THE ENGINE IS COLD.
Open the radiator cap and cover it with a rubber lid, this will force any pressure produced by the compression stroke into the coolant reservoir. Look for any continuous flow of bubbles.

No bubbles, no HG leak.

 

[flintknapper]

Really sounds like your T-stat is stuck closed. Also, when refilling the radiator/cooling system, it is possible for air become trapped in the system if you don't elevate the front of the vehicle. I like to drive mine up on a pair of 'ramps' and let it idle with the radiator cap OFF for at least 15 minutes. This gives the coolant time to heat up, which will (should) open the T-stat and coolant can then circulate throughout the system bringing any trapped air with it (burps the system...if you will).

The hydrocarbon test kit your mechanic used (if like what you posted) can and WILL give a false positive if you get any coolant in the mix. This is easy to do if you don't drop the level of the coolant in the radiator at least 2-1/2"-3".

I have that very same kit and have used it multiple times. It does work...when used properly...but is NOT the final word in my opinion.

I'd change the T-stat (use OEM only), be sure to use a NEW O-ring gasket. Fill radiator, elevate front of vehicle, leave the radiator cap OFF at this point. Let engine idle for 15 minutes, but watch for signs of overheating. After the system has had time to 'burp', install radiator cap and let the engine cool down. Restart engine after an hour or so, watch for bubbles in your overflow tank. Let the coolant warm up again. Both upper and lower radiator hoses should be warm/hot if the T-stat has opened and your water pump is working correctly.

If you still have problems, then yes....a good used engine would be the way to go. By the time you do all the repairs necessary on your relatively high mileage engine, you could buy a good used one with lesser miles.

Of course 'miles' alone are not as important as how well 'maintained' the donor engine would be. But don't be a panic just yet, you have some testing to do and not a great outlay of cash at this point.

These engines are pretty tough.

 

[flintknapper]

Thanks for the .02.
The lack of circulation to and from the radiator and heater core could just be water pump? I'm wondering if heat could have jacked up the impeller....
.

No, not impeller. The seal perhaps....but that would show up as a leak at the 'weep hole' near the bottom (center) of the engine at the front. IF that is the case (and you have no head gasket or other issues) then just look at getting a complete Timing Belt Kit (includes water pump, TB, tensioner, Idler bearings, etc..).

Similar to this:
Amazon.com: Aisin TKT-021 Engine Timing Belt Kit with Water Pump: Automotive

Some kits also have a serpentine (drive) belt, cam and crank seals.

Install (or have installed) and drive it another 100K.

 

[beachcruiser]

Ok... just headed back to the shop and have a little more to add to the equation in terms of symptoms... Still working on Tstat and test:
- upon startup and up to temp no symptoms
- under load is where temps jump up, and unable to produce any heat from heater in cab.
- hoses also dramatically harden under load as if being pressurized.

What's the chance of a HG leak that only occurs under load?
Thanks again, and worst case I'm looking at a local donor engine w 100k mis and good compression numbers as a fall back and punt.

 

[savirc]

This is a stuck thermostat. If you had a head gasket leak you would have white smoke coming out of the exhaust and gummy white engine oil.

You have all the hallmarks of a stuck thermostat or clogged line.

a) no heater
b) bloated radiator hose
c) overheating during load

This all indicates lack of coolant flow.

 

[SWUtah]

let us know after you put in a new thermostat how it is working

 

[beachcruiser]

This is a stuck thermostat. If you had a head gasket leak you would have white smoke coming out of the exhaust and gummy white engine oil.

You have all the hallmarks of a stuck thermostat or clogged line.

a) no heater
b) bloated radiator hose
c) overheating during load

This all indicates lack of coolant flow.

Thanks.... Mech was adamant that tstat was a waste of time, so I've hauled car back to the house and will swap in Tstat tonight and check again. Thanks again for the input and advice and I'll update shortly.

 

[nissanh]

A stuck-close thermostat should still give heat to the cabin. When the engine is cold, the disk located at the end of the thermostat keeps the engine block and the heater line directly connected and open. At the opening temperature, the valve to the main radiator line opens while closing the direct connection between the engine block and heater line.
How old is the radiator? May be you have a clogged radiator?

 

[AMGAndrew]

Agreeing with the bad t-stat. The increased coolant system pressure found the weakest link, being the T(s) and faught it's way out.

Change t-stat, pull off the upper and lower radiator hoses, garden hose full blast into the upper radiator hose and flush out the radiator core for a minute just to be safe that the core isn't clogged. Reinstall the rad hoses, fill with water (garden hose water is fine for now), burp the system like mentioned before and hopefully you'll maintain regular opperating temp. If so, buy the Aisin TB/waterpump kit and whatever else you feel like replacing while you are in there and you should be good for another 100k miles.

 

[2001LC]

Do a compression and or leak down test. You'll know for sure if t-stat is waste of time.

 

[ponytl]

I've played with these 4.7s more than I ever expected that I would... I will echo the Tstat .... but... try this... run the truck with the radiator cap off you don't need pressure for cooling... just for good cooling... watch the coolant in the radiator... it should MOVE/ flow even with a bad water pump you should have some flow... if the stat is stuck closed, then you will have no flow... if you have consistent bubbles in the coolant that "could be" combustion gases (bad thing)
if you have no oil in your water and no water in your oil chances are you are fine... do the water pump and tb and you'll be good for another 100k miles

 

[beachcruiser]

A stuck-close thermostat should still give heat to the cabin. When the engine is cold, the disk located at the end of the thermostat keeps the engine block and the heater line directly connected and open. At the opening temperature, the valve to the main radiator line opens while closing the direct connection between the engine block and heater line.
How old is the radiator? May be you have a clogged radiator?

Radiator is original to the vehicle afaik... Well, here goes:

- installed the tstat and temps eventually worked their way up to 3/4 hot (hotter than typically mid temp reading). Exhaust appears to have a white vapor (although cool out I ran other vehicle to see how it's exhaust demonstrated at temp. Definitely less vapor from other).
-Left cap open at startup and there is no movement to liquid at all inside radiator except as temp started to warm it would swell and a handful of bubbles appear. Then back to still until next round of large bubbles. Occurred at semi regular intervals so not sure that this was burping....
-Losing decent amount of coolant into pan under vehicle but having trouble locating source... likely the already leaking water pump.
- no hot air in cabin at all.

 

[2001LC]

System is self burping:

Fill radiator to top and fill reservoir. Run engine until hot. Allow to cool down over night.
Repeat only filling reservoir 1/4 full or less this time.
Repeat only filling reservoir to lower line (cold line) this time.
Repeat until levels hold. This usually take two or three cool down cycles.
Cabin heat should blow hot once system is full of coolant and air has been purged (burped). If system will not hold coolant you'll not get cabin heat.

Note: Full reservoir is at top line (hot line). Hot means normal operating temp.


Does oil look normal?