2.9l bubbling in the reservior/recovery tank

88 XLT Ranger · Jun 27, 2015

Got questions for you fine TRS folks

I got a 1988 Ranger 4x4 with a 2.9l v6 I have lifter ticking but the issue is when I drive it never gets into the red on temp. When I get home shut it off a few minuts later it starts bubbling inside the reservoir tank and gains coolaint. I fire it back up and watch the tank go back down. I also feel bubbling in the upper radiator hose. It don't smoke out the exhaust the temp here in the mountains is in the 90's

Other question if I have to have the engine rebuilt at a an auto repair what is the cost pulling and re-installing? has anyone gone through this before?

Lone-Ranger · Jun 27, 2015

Start it while cold with the radiator cap off, if it bubbles while running, you've got an issue.

Spott · Jun 27, 2015

That sounds more like air in the coolant system than any kind of engine damage.

I'd start by trying to burp the system well, and see if that solves it.

Park the truck facing uphill on a good slope (as steep as you're comfortable with). Top off the radiator, and, while filling, squeeze and release the upper radiator hose several times. When it stops taking more coolant, fire up the engine and let it run for a couple of minutes. Lather, rinse, repeat.

You might want to repeat the entire process a few times, in between driving the truck and letting it come up to operating temperature, to open the thermostat and try and release more trapped air.

"Never getting to the red on temp" is a good and normal thing. Under regular use, my temp gauge never goes above "A" on the vertical "NORMAL" scale, about 30%. I have an 88 2.9 as well (I guess it's an 86/87/88 franken-truck, but it's fairly close to stock.) I can't promise that the PO put the right thermostat in, last time around, but it works well.

88 XLT Ranger · Jun 27, 2015

Lone-Ranger said:
Start it while cold with the radiator cap off, if it bubbles while running, you've got an issue.

I just did it took it off let it run a bit and watched it no bubbles

88 XLT Ranger · Jun 27, 2015

Spott said:
That sounds more like air in the coolant system than any kind of engine damage.

I'd start by trying to burp the system well, and see if that solves it.

Park the truck facing uphill on a good slope (as steep as you're comfortable with). Top off the radiator, and, while filling, squeeze and release the upper radiator hose several times. When it stops taking more coolant, fire up the engine and let it run for a couple of minutes. Lather, rinse, repeat.

You might want to repeat the entire process a few times, in between driving the truck and letting it come up to operating temperature, to open the thermostat and try and release more trapped air.

"Never getting to the red on temp" is a good and normal thing. Under regular use, my temp gauge never goes above "A" on the vertical "NORMAL" scale, about 30%. I have an 88 2.9 as well (I guess it's an 86/87/88 franken-truck, but it's fairly close to stock.) I can't promise that the PO put the right thermostat in, last time around, but it works well.

When I try to burp the system I let it run but it will push a lot of antifreeze out I fill it and it will do it again. This Napa antifreeze is not cheap I just tried it it ran until warm than pushed a bunch out

RonD · Jun 27, 2015

Test or change rad cap.

When coolant gets hot it expands, this creates pressure in the cooling system, which is good, rad cap holds in this pressure usually at 14psi(approx.), this pressure raises the boiling point of the coolant.

Without this pressure when you shut off the engine, so no more circulation by water pump, the coolant in the head can boil, if this happens it creates air bubbles in the system which travels to the highest spot, so upper rad hose and rad cap then out the overflow hose and into the overflow tank.

Center of Ford Temp gauge is about 215degF, generally a warmed up engine will run at 190-200degF, thermostat 192degF
So below 1/2 on the gauge.

Water boils at 212degF
50/50 water/coolant boils 223degF

Pressure adds 3degF per 1psi of pressure, so 14psi of pressure = 42degF added to boiling point
So 50/50 with 14psi pressure has 265degF boiling point

If your temp gauge is just below 1/2 when you shut off engine, head coolant can quickly heat up past 223degf and boil, if it is above 1/2 then it would boil almost immediately without pressure

Spott · Jun 27, 2015

88 XLT Ranger said:
I just tried it it ran until warm than pushed a bunch out

Don't let it get up to operating temperature with the cap off...or is it pushing out through the overflow, with the cap on?

Like RonD mentioned, maybe your cap isn't holding the pressure. A new cap is an inexpensive test.

88 XLT Ranger · Jun 27, 2015

RonD said:
Test or change rad cap.

When coolant gets hot it expands, this creates pressure in the cooling system, which is good, rad cap holds in this pressure usually at 14psi(approx.), this pressure raises the boiling point of the coolant.

Without this pressure when you shut off the engine, so no more circulation by water pump, the coolant in the head can boil, if this happens it creates air bubbles in the system which travels to the highest spot, so upper rad hose and rad cap then out the overflow hose and into the overflow tank.

Center of Ford Temp gauge is about 215degF, generally a warmed up engine will run at 190-200degF, thermostat 192degF
So below 1/2 on the gauge.

Water boils at 212degF
50/50 water/coolant boils 223degF

Pressure adds 3degF per 1psi of pressure, so 14psi of pressure = 42degF added to boiling point
So 50/50 with 14psi pressure has 265degF boiling point

If your temp gauge is just below 1/2 when you shut off engine, head coolant can quickly heat up past 223degf and boil, if it is above 1/2 then it would boil almost immediately without pressure

I got a new cap from Napa on it 13lbs I got a tester and it test fine the radiator is new Napa replacement and new tater pump

RonD · Jun 27, 2015

Before shutting off warmed up engine see where temp gauge is at, after shutting off engine and hearing the overflow bubbling(it isn't boiling, just bubbles from boiling), turn on key and see what temp gauge shows.
Don't use, N, O, R, M, A, or L, use below 1/2, 1/2, above 1/2, 3/4, ect...

You could have air trapped in head, when engine is cold remove rad cap and highest heater hose, at heat control valve if it has one or at firewall if not.
top up rad until coolant flows out heater hose and heater core, reattach hose
Top up rad put cap back on.

The 2.8l did have a poorly designed head as far as cooling passages, so it did have a hot spot that caused this problem, never read that about the 2.9l

If you can't find the source of the problem you may need to step up to 16psi cap

Big Jim M · Jun 27, 2015

I don't think the cold engine bubble test was explained properly.

Park with the radiator cap higher than any other part of the coolant system. Fill the radiator up to the very top so any bubbles MUST be visible coming out the small opening.
Have a water hose in hand with a very small trickle running. This is to keep the level of the coolant as high as possible. Now if any bubbles you WILL see them.

The big gushes of coolant tells me you have a compression leak!

If bubbles aren't seen then I suggest replacing the thermostat. Buy one with a hole in it to allow air to escape. If none are available drill the damn hole yourself with a 1'8 drill.
Big Jim

88 XLT Ranger · Jun 27, 2015

Big Jim M said:
I don't think the cold engine bubble test was explained properly.

Park with the radiator cap higher than any other part of the coolant system. Fill the radiator up to the very top so any bubbles MUST be visible coming out the small opening.
Have a water hose in hand with a very small trickle running. This is to keep the level of the coolant as high as possible. Now if any bubbles you WILL see them.

The big gushes of coolant tells me you have a compression leak!

If bubbles aren't seen then I suggest replacing the thermostat. Buy one with a hole in it to allow air to escape. If none are available drill the damn hole yourself with a 1'8 drill.
Big Jim

I appreciate all of you helping me out "Thank You" :icon_thumby:

I took and pulled the hose coming from the manifold to heater core off good amount of coolant coming out. I took and flushed the core out as well coolant coming out both hoses and core it was still warm. I left the radiator down 1" from top fired it up let it run as I was pushing the upper hose together I felt it gain coolant inside the hose. Than as it warmed up the coolant started to rise I put the cap back on. I drove it after running and hot 6 miles to town the temp was a little below half way mark stopped turned it off no bubbling turned to key on it was 3/4 on temp. I fired it up lifters licking loud running like crap than 3 min into driving quite running great. I get home shut it off no bubbling opened the hood felt the upper hose feel bubbling than here she comes into the reservoir bubbling but this time not as much as before

On my lifters they have adjustable rocker arms? can I adjust them tighter to get the lifter tapping down? or will this make for more serious issues? I got smog check next month and with the lifters ticking bad at times it might not pass I don't know

RonD · Jun 27, 2015

2.9l is a bit of an odd ball with lifters, they are hydraulic but have adjusters on the rockers.

So yes you can adjust them, but they will still "tick".
The problem is in the cam bearings, they feed the lifters oil passages to keep them pumped up with oil, after about 80k miles the cam bearings are worn enough to allow more oil to pass thru between bearing and cam, the oil pressure at the lifters drops enough to keep the lifters below "ticking" pressure, so you get "ticking".
If you adjust them at idle to get rid of the "ticks" then when RPMs increase oil pressure does to and now the valves are not closing long enough, so engine runs like "sh!t".

It would be worth spending an afternoon doing an engine off adjustment.
When both valves on a cylinder are closed, set rocker to 0 lash
Then turn adjuster one and a half turn in, 1 full turn and 1/2 of another full turn
This will collapse lifter about half way, normal for hydraulic lifters.
Some with older 2.9l engines do 1 full turn then 3/4 of another full turn, that should be fine.

You could also run 10w-40 oil, that will bring up oil pressure a bit at idle, could quiet it a bit

"Ticking" lifters on a 2.9l shouldn't effect smog test, 27 year old engine and emission system will effect it more

Smell the overflow tank when it is bubbling, see if it has an exhaust smell, so cracked head or bad head gasket.
If you do a search on the site for Glove Test you will find a free test you can do just to eliminate that possibility, or to confirm it

88 XLT Ranger · Jun 28, 2015

RonD said:
2.9l is a bit of an odd ball with lifters, they are hydraulic but have adjusters on the rockers.

So yes you can adjust them, but they will still "tick".
The problem is in the cam bearings, they feed the lifters oil passages to keep them pumped up with oil, after about 80k miles the cam bearings are worn enough to allow more oil to pass thru between bearing and cam, the oil pressure at the lifters drops enough to keep the lifters below "ticking" pressure, so you get "ticking".
If you adjust them at idle to get rid of the "ticks" then when RPMs increase oil pressure does to and now the valves are not closing long enough, so engine runs like "sh!t".

It would be worth spending an afternoon doing an engine off adjustment.
When both valves on a cylinder are closed, set rocker to 0 lash
Then turn adjuster one and a half turn in, 1 full turn and 1/2 of another full turn
This will collapse lifter about half way, normal for hydraulic lifters.
Some with older 2.9l engines do 1 full turn then 3/4 of another full turn, that should be fine.

You could also run 10w-40 oil, that will bring up oil pressure a bit at idle, could quiet it a bit

"Ticking" lifters on a 2.9l shouldn't effect smog test, 27 year old engine and emission system will effect it more

Smell the overflow tank when it is bubbling, see if it has an exhaust smell, so cracked head or bad head gasket.
If you do a search on the site for Glove Test you will find a free test you can do just to eliminate that possibility, or to confirm it

Thanks Ron

The coolant bubbling in the reservoir has no exhaust smell just hot antifreeze smell. On the rocker arm adjustment when cold if I take the coil wire off turn in over until on cylinder valves are closed meaning slack on both rocker arms. Adjust one full turn on the adjusters? I also have bars leak head gasket and cracked head repair the copper stuff in my radiator this was a big plus as I though it was a cracked head

RonD · Jun 28, 2015

You start at 0 lash when adjusting rockers.
Cam must be at it's low point when adjusting it's valve
0 lash means you loosen the adjuster until rocker can be moved, so there is a gap between rocker and valve stem, then tighten adjuster so there is 0 gap(0 lash), i.e. rocker can't "rock" but there is no pressure on valve stem or push rod.
Then you turn adjuster one full turn tighter, and then half a full turn tighter, so 1.5 turns tighter.
Or 1.75 turns tighter, your choice.

The big thing is making sure cam lobe for that valve is at it's lowest point, or adjustment will be wrong.

You can lift up distributor cap and turn engine so rotor is pointed at #1 spark plug wire, so #1 would be firing, this means #1 intake and exhaust valves are closed to hold the pressure in, adjust #1 rockers.
Then turn engine until next spark plug wire lines up with rotor, #4, and adjust it's valves, then turn engine until next spark plug wire lines up with rotor, #2, ect.......

You are following the Firing Order 1-4-2-5-3-6 around the cap, there are other ways to do this, but this is just easier to do and doesn't take that much longer

Have the heads ever been worked on as far as you know?
Just wondering if someone "over did it" with gasket sealer on a head gasket and blocked a few coolant passages, so you are getting a hot spot.

Assuming 50/50 water/coolant and 13psi cap, coolant in head would have to be above 250degF to boil, which can happen just after shut down of engine if it was hot in that one area of the head.
Do spark plugs show carbon build up?
If you have an EGR system does it seem to be working, i.e. no pinging or knocking when accelerating?

BAR's or other head gasket sealers are fine to use, but are temporary fixes for a cracked head or head gasket leak, they work on the principle that the sealer, like a liquid glass, will be subject to the 1,000degF temp of a cylinder as the coolant is sucked in on an intake stroke.
If you don't have the white smoke out the exhaust pipe then not enough coolant is being sucked in to get a good seal from products like these.
So if the overheating is caused by cracked head or head gasket issue then it will have to get worse(which it will) before Bar's can work, or this isn't a cracked head or head gasket issue.

And as much as I hate to say it...............you may be better off with a 180degF thermostat if you haven't got one already

88 XLT Ranger · Jun 28, 2015

RonD said:
You start at 0 lash when adjusting rockers.
Cam must be at it's low point when adjusting it's valve
0 lash means you loosen the adjuster until rocker can be moved, so there is a gap between rocker and valve stem, then tighten adjuster so there is 0 gap(0 lash), i.e. rocker can't "rock" but there is no pressure on valve stem or push rod.
Then you turn adjuster one full turn tighter, and then half a full turn tighter, so 1.5 turns tighter.
Or 1.75 turns tighter, your choice.

The big thing is making sure cam lobe for that valve is at it's lowest point, or adjustment will be wrong.

You can lift up distributor cap and turn engine so rotor is pointed at #1 spark plug wire, so #1 would be firing, this means #1 intake and exhaust valves are closed to hold the pressure in, adjust #1 rockers.
Then turn engine until next spark plug wire lines up with rotor, #4, and adjust it's valves, then turn engine until next spark plug wire lines up with rotor, #2, ect.......

You are following the Firing Order 1-4-2-5-3-6 around the cap, there are other ways to do this, but this is just easier to do and doesn't take that much longer

Have the heads ever been worked on as far as you know?
Just wondering if someone "over did it" with gasket sealer on a head gasket and blocked a few coolant passages, so you are getting a hot spot.

Assuming 50/50 water/coolant and 13psi cap, coolant in head would have to be above 250degF to boil, which can happen just after shut down of engine if it was hot in that one area of the head.
Do spark plugs show carbon build up?
If you have an EGR system does it seem to be working, i.e. no pinging or knocking when accelerating?

BAR's or other head gasket sealers are fine to use, but are temporary fixes for a cracked head or head gasket leak, they work on the principle that the sealer, like a liquid glass, will be subject to the 1,000degF temp of a cylinder as the coolant is sucked in on an intake stroke.
If you don't have the white smoke out the exhaust pipe then not enough coolant is being sucked in to get a good seal from products like these.
So if the overheating is caused by cracked head or head gasket issue then it will have to get worse(which it will) before Bar's can work, or this isn't a cracked head or head gasket issue.

And as much as I hate to say it...............you may be better off with a 180degF thermostat if you haven't got one already

Ron and the rest of you I thank all very much for the great help. I am working on checking oil pressure once I get the parts. Ron no the engine has never been worked on the heads all stock. Today I took and drained the antifreeze first off I notice the drain was not leaking much. I pulled the drain plug out still not much I took and pushed together the upper hose a few times than it flowed out. I noticed like little rock looking stuff and like aluminum crap in the bucket. I than took and removed the brass rattle valve in the thermostat to give it a fee flowing small hole. I put it back together filled the radiator keeping it 1" below the top. I started it let it run with heater on. I notice on the radiator the side going into the intake upper hose was hot and the other side filler and lower hose cold. I did push the upper hose together a lot than and lower hose its started getting hot. I drove it in the heat for a bit shut it off I can feel bubbling in upper hose but only one bubble burp in recovery tank . It was a lot better than before and lifter where much better on ticking

I think I need the 101 on radiator flushing as my last effort was not right I have the automatic trans radiator. This Ranger is real clean XLT dark red and dark silver bottom two tone. I love my truck original interior like new I got to save it its family

any and all help is so much appreciated from you fine folks

2.9l bubbling in the reservior/recovery tank

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