MIDAS blew up my Jeep ...

[BulletMaker]

Borax (typically sodium borate) won't form glass at the temperatures you see in an engine, in general borax is a water conditioner, which helps remove calcium and other heavy alkali salts. I can totally see it used as a cleaner and general coolant additive (will help break the surface tension of the water, and allow it to stick to oily parts) but I can't really think of any good use where it would act as a sealant.

Despite the listing of the active ingredients, I think there is probably some fine grit like corncob media or perhaps some mineral that doesn't have to be listed on the MSDS but is present in order to act as a stop-leak. It's one of those cases where they have to list the "chemicals", I didn't notice what the balance (80%) is.

As to the bubbling issue, if you open up the bottle, once you turn the engine on the coolant loop that runs through the bottle is constantly running. As the coolant bottle water runs either through the coolant bottle, or through the heater core until the T-stat heats up enough to open (at which point it enters the radiator). So any air, could be bubbles from the water pump, air that was trapped in the block, etc. The important thing to take away from this test would be to check if exhaust gasses are present in the fluid (which was the claim of the shops you took it to, personally I think they don't know wtf they are talking about).

 

[joe_peters]

Have NAPA look up head bolts 96+, they work perfectly. NAPA no. FPG ES71102

 

[FlyNNN]

Temp. numbers are in (C);
Number below taken at same time as number above.

Two measurements;
Back head 108 -- 118
dash gauge 110 -- 118

Three measurements;
Lower rad hose 37 -- 40 -- 48
Upper rad hose 77 -- 80 -- 86

Driver side rad 42
Thermostat housing 70
Head front 134
Coolant bottle 38

Also of note, I turned the heater on in the dash. Not once did the e-fan turn on. When the AC is turned on, the e-fan then kicks in.

It is antifreeze (5-10% ethylene glycol) mixed with 5-10% Borax. I have no experience with that stuff, so I can not recommend it. It IS NOT the product I suggested, nor does it seem to even be similar!!!!

Yes, I know. I don't think its in my area. I tried to call the manufacturer but got a dead line. I found on eBay but thats two weeks away. I went with what was recommended. This stuff doesn't seem to have made any difference. Maybe yours would have, I don't know.

As to the bubbling issue, if you open up the bottle, once you turn the engine on the coolant loop that runs through the bottle is constantly running. As the coolant bottle water runs either through the coolant bottle, or through the heater core until the T-stat heats up enough to open (at which point it enters the radiator). So any air, could be bubbles from the water pump, air that was trapped in the block, etc. The important thing to take away from this test would be to check if exhaust gasses are present in the fluid (which was the claim of the shops you took it to, personally I think they don't know wtf they are talking about).

I guess I didn't notice it before. Only had it in since last summer. I guess I'm still learning about it's peculiarities.

Also, since it sounds like you don't do a lot of maintenance yourself, you probably want to maintain a higher antifreeze/water ratio, ... Another thing you want to think about is opening the radiator cap (when engine is cold) and turning it on, waft the gasses coming out of the bottle and smell for exhaust or gasoline fumes.
Let us know how that oil comes out looking, as that's the surest sign of a bad head gasket in my opinion. Also, I don't remember if you stated what the current coolant level is, do you see it in the bottle? (or when you open the cap) I think that's the one downside to having the nicer bottle.

Ouch! That stings a little. I try to maintain my vehicle ... my profession is IT troubleshooter not Jeep mechanic. Forgot to waft for gases. From recollection, I don't recall there being anything noticeable on previous occasions when the cap was off. Didn't check level in bottle this time but it was usually half full. Forgot to check oil. Will have to wait for cool down.

Have NAPA look up head bolts 96+, they work perfectly. NAPA no. FPG ES71102

Thank you. I told the guy at the parts desk that I'll find him a number one way or another.

 

[Ecomike]

Have NAPA look up head bolts 96+, they work perfectly. NAPA no. FPG ES71102

I was under the impression the Renix head bolt set was different?

I got mine at www.headbolts.com
Only place I could find them.

 

[Ecomike]

You may be right about unlisted ingredients, etc....., but I don't recommend using unknowns!!!

If there is an exhaust leak past the head gasket to the coolant, the exhaust heat and loss of water at the gas-liquid interface will cure the Borate and silicate and form a boro-silcate glass solid, but the silicate will do that anyway. What is missing from the ingredient list is the fibers!!!!!

Sounds like you know some chemistry?

Borax (typically sodium borate) won't form glass at the temperatures you see in an engine, in general borax is a water conditioner, which helps remove calcium and other heavy alkali salts. I can totally see it used as a cleaner and general coolant additive (will help break the surface tension of the water, and allow it to stick to oily parts) but I can't really think of any good use where it would act as a sealant.

Despite the listing of the active ingredients, I think there is probably some fine grit like corncob media or perhaps some mineral that doesn't have to be listed on the MSDS but is present in order to act as a stop-leak. It's one of those cases where they have to list the "chemicals", I didn't notice what the balance (80%) is.

As to the bubbling issue, if you open up the bottle, once you turn the engine on the coolant loop that runs through the bottle is constantly running. As the coolant bottle water runs either through the coolant bottle, or through the heater core until the T-stat heats up enough to open (at which point it enters the radiator). So any air, could be bubbles from the water pump, air that was trapped in the block, etc. The important thing to take away from this test would be to check if exhaust gasses are present in the fluid (which was the claim of the shops you took it to, personally I think they don't know wtf they are talking about).

 

[BulletMaker]

Temp. numbers are in (C);
Number below taken at same time as number above.

Two measurements;
Back head 108 -- 118
dash gauge 110 -- 118

Three measurements;
Lower rad hose 37 -- 40 -- 48
Upper rad hose 77 -- 80 -- 86

Driver side rad 42
Thermostat housing 70
Head front 134
Coolant bottle 38

Also of note, I turned the heater on in the dash. Not once did the e-fan turn on. When the AC is turned on, the e-fan then kicks in.

Was the temp gauge peaking when this was going on? Because this is starting to sound like a bad gauge/sensor/wiring. ~180F is what I get with my jeep up to normal temp. On the T-stat housing, Even though it's showing 120C at the back, I'm guessing you're probably picking up a little bit of the exhaust manifold and that's why it's showing the higher temp.

IIRC the temp sender is cheap (<10$) might want to replace it to take that out of the loop, alternatively you could test it with a multi-meter, and you could test your harness/gauge by using a rheostat (a variable resistor). The temp gauge works by having positive voltage across it, and measuring the current it sends to ground by way of a thermal resistor in the temp sender.

Ouch! That stings a little. I try to maintain my vehicle ... my profession is IT troubleshooter not Jeep mechanic. Forgot to waft for gases. From recollection, I don't recall there being anything noticeable on previous occasions when the cap was off. Didn't check level in bottle this time but it was usually half full. Forgot to check oil. Will have to wait for cool down.

Thank you. I told the guy at the parts desk that I'll find him a number one way or another.

Sorry man, wasn't trying to dig ya on that one.

I'm really starting to get the feeling that the issue here is either unrelated to your replacement of the exhaust system, and may be more related to electrical/grounding issues, a bad temperature sender, and less to do with actual overheating. If you want to be doubly sure, turn it on, run it for about 5-10 mins (until the gauge says it's pushing an overheat) and with the engine running SLOWLY open the cap (use a big rag) once the cap is off, stick a candy thermometer in there (this is like a regular thermometer, but usually measures temps over that of boiling water). If this shows temps under 100C I think your temp sender/wire/ground is bad.

As long as you're at it, and just for completeness check your ground strap, this is usually a metal braid looking thing near the MAP sensor, there is also usually one near the oil filter, if they are excessively dirty or showing signs of corrosion replace them with some good battery cable grounding wires (available at pretty much every auto part store).

The justification I have for my theory on this, is the temp sensor works by controlling resistance to ground from the gauge, if there is a grounding issue, there may be more current finding ground by way of the gauge which would show a higher temp whether there was or not.

I remember some years ago I was driving around in my old mazda B2000... I was somewhere in texas when the car started telling me it was overheating, I was rather surprised as it was a cool day on a flat road, checked the oil, pulled the release on the cap, and didn't really have much steam come out. I babied the thing all the way to colorado checking everything frequently, all of that trouble ended up being caused by a $8 part.

On the other hand, I was driving my old suburban around, it started to say it was overheating, so I pulled over, opened the hood, and turned it off. About 2-3 mins into this the excess pressure of the coolant boiling blew the feed hose right off the radiator and sprayed everything with boiling coolant. I'm not sure if that was the car's way of telling me I had a blown head gasket, or if caused the blown gasket, but it was a spectacular failure, about a week later I found coolant in the oil.

BTW, did you check your oil to see if there is enough oil in it, and whether it's milky or anything?

 

[Ecomike]

This is starting to really look like a stuck closed or nearly closed Thermostat!!!! Or a water pump where the impeller is spinning loose on the shaft, or the back wards style water pump installed....Looks like you are not getting coolant flow!!!!

The question now, is why isn't it flowing?

Clogged radiator, stuck T-stat (stuck closed or nearly closed, they do fail!!!!!, and many are bad off the shelf from China lately!!!!).

The low temp on the coolant bottle has me thinking the water pump is not working as the bottle should see flow if plumbed up to OEM specs (but, you have an aftermarket plumbing job-tank so maybe not?), with out the cold bottle temp, I would suspect the T-stat to be stuck closed.

Great temp data by the way!!!!!!!

Mine would typically be 95 C in the engine (+/- 5 C) and 90 C going into the radiator and 80 C coming out of the radiator. Mine works great, perfect in fact, in 105 F heat waves outdoors, 90% humidity, 5 mph traffic for an hour with the AC on max. Never gets over 100 C coolant temps.

Temp. numbers are in (C);
Number below taken at same time as number above.

Two measurements;
Back head 108 -- 118
dash gauge 110 -- 118

Three measurements;
Lower rad hose 37 -- 40 -- 48
Upper rad hose 77 -- 80 -- 86

Driver side rad 42
Thermostat housing 70
Head front 134
Coolant bottle 38

 

[FlyNNN]

Sorry, out back staining my Redwood deck ...

Was the temp gauge peaking when this was going on? Because this is starting to sound like a bad gauge/sensor/wiring. ~180F is what I get with my jeep up to normal temp. On the T-stat housing, Even though it's showing 120C at the back, I'm guessing you're probably picking up a little bit of the exhaust manifold and that's why it's showing the higher temp.
IIRC the temp sender is cheap (<10$) might want to replace it to take that out of the loop, alternatively you could test it with a multi-meter, and you could test your harness/gauge by using a rheostat (a variable resistor). The temp gauge works by having positive voltage across it, and measuring the current it sends to ground by way of a thermal resistor in the temp sender.

I'm really starting to get the feeling that the issue here is either unrelated to your replacement of the exhaust system, and may be more related to electrical/grounding issues, a bad temperature sender, and less to do with actual overheating. If you want to be doubly sure, turn it on, run it for about 5-10 mins (until the gauge says it's pushing an overheat) and with the engine running SLOWLY open the cap (use a big rag) once the cap is off, stick a candy thermometer in there (this is like a regular thermometer, but usually measures temps over that of boiling water). If this shows temps under 100C I think your temp sender/wire/ground is bad.

As long as you're at it, and just for completeness check your ground strap, this is usually a metal braid looking thing near the MAP sensor, there is also usually one near the oil filter, if they are excessively dirty or showing signs of corrosion replace them with some good battery cable grounding wires (available at pretty much every auto part store).

BTW, did you check your oil to see if there is enough oil in it, and whether it's milky or anything?

- Dash temp gauge was mid red, same as picture on p3 of this thread. My IR gun doesn't have a laser pointer so it is a little difficult finding the spot I'm looking for. The way I read it, the dash gauge is spot on according to the results. I think I have a sensor in my parts box, I'll dig around for it.
- No candy thermometer around here, that will have to wait. Wonder if the IR gun could read it? I would be leery of removing that cap early though. I just removed it after sitting for an hour and there was still a lot of pressure and heat.
- I checked/cleaned the ground straps last year, I'll take a second look.
- I checked the oil from the dipstick, looked OK. Do you think that's a large enough sample? It's time I remove the winter oil and put in some 10-30 anyways. I'll do it tomorrow.
- I checked the coolant but that additive I put in was a grey mass and I'm sure has skewed how it now looks.

This is starting to really look like a stuck closed or nearly closed Thermostat!!!! Or a water pump where the impeller is spinning loose on the shaft, or the back wards style water pump installed....Looks like you are not getting coolant flow!!!! The question now, is why isn't it flowing?

The low temp on the coolant bottle has me thinking the water pump is not working as the bottle should see flow if plumbed up to OEM specs (but, you have an aftermarket plumbing job-tank so maybe not?), with out the cold bottle temp, I would suspect the T-stat to be stuck closed.

The metal coolant bottle is extremely hot and too much to touch. I wouldn't necessarily call it a low temp. Maybe my one reading is not correct but that bottle is hot and pressurized. I checked the upper rad hose again and it felt more pressurized that the last time I squeezed it. So are we leaning towards looking at the thermostat? ... and I'm guessing while I am there the water pump as well? ... of which I have neither on hand.

 

[Ecomike]

I disagree with BulletMaker on this one. The ultra low radiator and radiator outlet hose temps are a dead give away that coolant is NOT flowing, so either the Radiator is plugged up or the T-stat stuck.

Since it was a sudden change at the muffler shop, my money is on a sudden death stuck thermostat, which is typically how they die, with no warning. And I think a stuck T-stat can damage a head gasket that is already weak with out blowing up the coolant system.

Pull the T-stat and stick it in boiling water to see if it ever opens. You can leave the T-stat out till you get a new one, to drive the jeep, but you will need a new gasket, or need to make a temp gasket with silicone, so use the copper silicone or get a gasket.

 

[FlyNNN]

I disagree with BulletMaker on this one. The ultra low radiator and radiator outlet hose temps are a dead give away that coolant is NOT flowing, so either the Radiator is plugged up or the T-stat stuck.

Since it was a sudden change at the muffler shop, my money is on a sudden death stuck thermostat, which is typically how they die, with no warning. And I think a stuck T-stat can damage a head gasket that is already weak with out blowing up the coolant system.

Pull the T-stat and stick it in boiling water to see if it ever opens. You can leave the T-stat out till you get a new one, to drive the jeep, but you will need a new gasket, or need to make a temp gasket with silicone, so use the copper silicone or get a gasket.

If the thermostat is stuck closed, wouldn't the upper rad hose be empty with no hot coolant? Makes more sense to me that the rad is the impediment in this loop. Please elaborate.

 

[heyhar]

To beat a dead horse, does the Renix system use the Tstat with the check-ball bleeder in it? I've found in my XJs, and even my Subie, that systems originally equipped with the bleeder ball really do like it better! Just my $0.02.

 

[MaxxXJ]

To beat a dead horse, does the Renix system use the Tstat with the check-ball bleeder in it? I've found in my XJs, and even my Subie, that systems originally equipped with the bleeder ball really do like it better! Just my $0.02.

I found that changing your system to an open system vs a closes system that renix likes it better I hated fighting with it and cracking that stupid bottle once a year.

 

[DrMoab]

I found that changing your system to an open system vs a closes system that renix likes it better I hated fighting with it and cracking that stupid bottle once a year.

This is the best advice I've seen in this thread. Get rid of that stupid bottle !!

 

[MaxxXJ]

This is the best advice I've seen in this thread. Get rid of that stupid bottle !!

New open radiator, new hoses, new water pump new thermostat and new ZJ fan upgrade...now my jeep rides here when im moving. And I have 260,000 miles on my original motor!

 

[magimerlin]

I was under the impression the Renix head bolt set was different?

I got mine at www.headbolts.com
Only place I could find them.

Mike,
Not to get off topic from the op but... All the head-bolts are the same size and length through out the years. The only difference is that the newer ones have a short stud alignment stub on the tops of them for the newer style valve cover gasket that gets held in place/aligned by the posts.

Both of my 1989 Xj's when I did their head gaskets I used the newer style bolts. Both are still going strong...

We used the same head bolt kit in the 98, 96, and a 91 that we did over my buddies place.

Needless to say I have done a few head gasket jobs....lol

 

[POSJ]

Biggest problem I see is blaming a shop for a vehicle problem...XJ's overheat, fix it, it was bound to happen eventually.

 

[FlyNNN]

Biggest problem I see is blaming a shop for a vehicle problem...XJ's overheat, fix it, it was bound to happen eventually.

I disagree with your black and white assessment. When you take a vehicle in good working condition and its returned to you defective + $417 for a $100 muffler job, one gets a little pissed. If there are new problems discovered, inform me so I can make a decision, just don't hand me the keys and see' ya.

- MaxxXJ, would be nice to see my temp gauge on the left side of center.

Anywhoo ... I have some positive news to report. I did a lot of bike riding today, 30 minutes one way to get my parts. Had to make two trips. Second one for a over-priced FRAM filter which I couldn't install anyways. My two brand new NAPA Gold's wouldn't screw on so I had to stick the old filter back on.

First, I replaced the coolant bottle rad cap, as Ecomike recommended, to another 16lb and I noticed some improvement. When the thermostat opened, it took a little longer for the temp to inch up and it idled below the red mark. Although, when I went for a spin around the block, the temp inched back up to the red mark. Temp on the coolant bottle was up a couple of degree's to 41 as compared to 38 before. This is an improvement.

Second, I changed oil using 10w30 synthetic which I have been using for 20 years in this vehicle and another improvement was noticed. Idle is a couple of degree's cooler. Took vehicle for a spin around the block and needle stayed out of the red zone, this is an improvement.

Other notes; I noticed what appears to be water at the exhaust. I don't recall seeing this before. Looking at the old oil, I really didn't noticed anything differnet than my last 500 changes.

I picked up a 180 and a 192 thermostat. I'll see what I can do about that tomorrow. I'll make a last minute decision on which one I install. I still wonder about this as it appears the thermostat is doing what it is suppose to be doing. See pic below for latest dash gauge view. 1/2 way there to getting the needle back to the centre.

 

[POSJ]

FlyNNN you assume that this trip wasn't the last trip before it let go. A lot is circumstantial, I drove my Jeep fine to the gym one day and then it didn't start. Stuff happens bud...You over paid for a muffler job and you blame them? Shop around. Not trying to flame you at all but you seem to think that somebody is to blame for a 20+ year old vehicle(you said you have been putting synthetic in for 20 years) having an issue. Expect an XJ you break, don't expect it not to. People here are willing to help as you have seen but I doubt Midas is the cause.

 

[Ecomike]

flyNNN,

Do me a favor, and check to see if the muffler shop some how made the exhaust system leak and start blowing exhaust on the engine block!!!!

I went to a muffler shop I trust and watched them check for exhaust leaks 3 times, and we did not find a leak. After multiple upgrades on mine, I discovered by accident that the flange donut between the manifold and the exhaust pipe was bad, real bad, and was blowing exhaust on the oil pan about 3/4" away from the donut. It showed up more at higher RPMs.

Someone here recently shot something (gumout?) into their intake that made smoke and their found their overheating issue from the smoke that came out the exhaust in the same place.

Since the exhaust was worked on at the time, it might be part of the problem. I still think the T-stat is bad.

 

[Ecomike]

If the thermostat is stuck closed, wouldn't the upper rad hose be empty with no hot coolant? Makes more sense to me that the rad is the impediment in this loop. Please elaborate.

I see no reason a T-stat can not get stuck partly open. Some junk in the block could come loose and jam it.