Radiator overflow not returning to radiator overnight

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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philip
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#16

Post by philip »

ecomike wrote:So does the SD-22 (at least mine does). This is not a 4.0 jeep engine(?), it is an SD-22 in a jeep with a jeep downflow radiator. Did I miss understand you?
Some people mistake for putting a cap that has NO rubber seal. These mistake cap will have a brass disk. If you have a brass disc, there will be some air vacuumed as hot coolant cools down.

Next ... all the radiator "spring pressure" will have the spring pressure "rubber seal" and the little metal disk loading vacuumed coolant. Note this little disc has a very weaked spring also. The disc must not floppy.

Check these Jeep listings: http://www.discountjeepparts.com/index. ... th/33_1897

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Last edited by philip 17 years ago, edited 2 times in total.
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davehoos
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#17

Post by davehoos »

These caps often leak AIR through the riviot on top.paint dribbled around will seal them.this is not a pressure area so water leaks are unusual.the nissan cap once had a sticker that you could see getting drawn in.

rubber seal not contacting/sealing could be as simple as the neck deforming over time,not allowing it to seat.i had trouble getting these to seal after refilling with coolant.they had volcalised together overtime and I used a large wrench to undo.

some models have different depth in the filler neck.also the shape of the sealing contact area change.

the return when cold disc can stick closed.

RE previos post.I cant coment on the USA sold jeep[or datsun] as the australian sold RHD wont be the same and has diffent specs,just generic information.jeep was discontinued in australia for many years being built in brisbane QLD from mexican parts...the 4.0 liter 6cyl was designed in australia by chrysler.A friend in LA had one of the first sold there[he traded a V6] it was in the dealer several times to replace fuel tanks when i visited.
the jeeps sold here under the chrysler badge are made in austria and maybe mexico there was talk of the chinese model but i think it didnt get built in RHD.,korean asia motors ROCSTA has a mazda and nissan TD27 engines.some indian jeeps had 4.0 ford falcon 6cyl.
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ecomike
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#18

Post by ecomike »

Nice pictures Philip! Good to see you back in the fray here!

I think I already mentioned that I have tried multiple radiator caps. They all had two rubber gaskets...etc. Differences were I tried, 13, 15, 16, and I think 18 lb caps that had the same seal shape (they all fit the jeep radiator correctly). The only other difference being that some of them, including the one I currently use have the manual pressure release lever on top for safely, manually releasing the pressure to the overflow bottle when the system is hot and under pressure.

I am currently using the 13 lb cap that the SD-22 FSM, 1982, calls for and not the 15 lb cap the Jeep FSM calls for, but I have tried both in the past.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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ecomike
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#19

Post by ecomike »

The good news is the radiator is holding up.

I had to get her up on the freeway for 30 miles, A/C on, Condenser fan off (I have a manual switch for it), ambient at about 83 F, to get her hot enough to get flow into the overflow bottle. (Yes philip, I still have a 165 F thermostat in there, the OEM 192F is still in the "roundtoit" box, partly because I wanted to solve some other problems like this one before swaping it out). But interestingly enough this rig runs like a champ even at 165 F.

Back to the problem. So after the 30 mile trip I got about 2" of liquid level increase in the 1 quart overflow bottle (about 1/2 to 1/3 of a pint). Left it overnight, and by noon the next day the fluid was still in the overflow bottle, non of the coolant had returned to the radiator. I know the overflow hose and nipples are good and air tight. Also the upper and lower radiator hoses were not collapsed (under vacuum). In fact by the time I check the system it had warmed up a good 30 degrees F from the overnight lows, and the upper hose felt like it had maybe 1 lb of pressure back on it. Engine had been off for nealy 20 hiurs by then.

I am going to try it once more before I make any changes. Then I think I am going to flush the entire system real good, replace the radiator cap (it is about 2 years old now) and try it again before deciding it must be the pump seal or little blue demon gremlin devils busy doing their thing.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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ecomike
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#20

Post by ecomike »

Well have tried enough different caps that I thought I had rulled that out, but I may just have to try sealer on the top of the cap rivet just to to be sure. Interesting to note that I found a 50% defect rate in the new radiator caps at 2 stores (O'Reilys and autozone) last week. 50% of the 13 and 15 lb caps they had, had totally loose, dangling "disk vent return plates", absolutely no spring pressure to seal them as the coolant heats up, meaning their would be no effective cap pressure on the radiator they were used on at all! Makes me wonder what else is wrong with them.

I have already bought a new water pump, the good one, cast iron "N" style. Planning to replace it and the intake/exhaust manifold gasket and exhaust manifold to exhaust pipe flange stud bolts all at one time sometime in the next 2 weeks.

The 2nd and 3rd overflow return test also failed, so it is looking like the water pump seal (I am hoping it is at this point!), is leaking in one direction only, namely allowing air to e sucked in during cool down.

The good news is the repaired radiator and the rest of the cooling system and A/C system is holding up nicely. I have to get on the freeway at WOT (4th or 5th gear) with the A/C on full blast and at 80F ambient minimum for at least 15 minutes just loose a coffee cup of coolant to the overflow bottle. And after an hour at WOT..... that is still all it looses to the oveflow bottle. It got to 93 here today.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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#21

Post by moose60 »

an HOUR at WOT?!!?

I don't like to drive my truck 80+. Even crossing passes in the NW with a 4000' elevation change, I rarely drop below 45 mph and WOT runs are less than 12-13 minutes at once (this is on the Vantage Grade on I90, 10 miles of 4-5%).
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ecomike
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#22

Post by ecomike »

moose60 wrote:an HOUR at WOT?!!?

I don't like to drive my truck 80+. Even crossing passes in the NW with a 4000' elevation change, I rarely drop below 45 mph and WOT runs are less than 12-13 minutes at once (this is on the Vantage Grade on I90, 10 miles of 4-5%).
I don't have an accurate speed reading yet on mine (Keep in mind it is an SD-22 dropped into a 1985 Jeep Chreokee Pioneer, 2WD, so the odometer is not hooked up, and would not be acurate if it was, but I think it is topping out on a flat run at about 70 mph with the A/C on, and 75 mph tops with the A/C off.

Actually the increase in MPHs in 5th gear between 50% and 100% WOT is pretty dismal in my case, so I am actually running at 50 to 80 % WOT. Up hill at overpasses with the A/C on I run closer, like maybe 90% WOT, then back off to 50% of WOT on the downside of the overpass, as I maintain a steady speed of 60 to 70 MPHs. So I guess you got me on that one. What I should have said was with the engine about as fully loaded as I ever run it.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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ecomike
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#23

Post by ecomike »

Well I just went out to put some sealer on the top rivet of the coolant cap, as suggested but I could not do so as I have a lever / pressure release tap on top of the cap, style cap on mine at this time. Putting 2 and 2 together, I am now wondering if this style cap leaks at the top (it has moveable shaft, and must or should have some kind of seal there on the shaft) worse than one with a fixed a rivet?????

Planning to retry a standard style cap (no spring loaded pressure release lever on top) again, which I have not tried since I got the radiator serviced!

Edit: Well its installed will post test results in a few days on this.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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Flush cautions

#24

Post by FedExCF6Mech »

Slightly OT, I helped a friend do a radiator clean and flush on a 280zx. He had one of those adaptors that hooks into the heater hose so you can "power flush" the system. The only problem is the radiator system is designed for, what 15 lbs and the city water line runs about 60 psi! Well, you can guess what happened. He did NOT have the drain petcock open when he turned the water on and 2 cylinders filled up with water. When I pulled the spark plugs out and had him try to crank it the water squirted out and hit the house next door! It is probably less likely on a diesel with the higher compression but DON'T take that chance!
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#25

Post by kassim503 »

im surprised the head gasket leaked from that, cause the cylinders are built to handle 150+ psi on the compression stroke.

Sure as hell dont sound like there was a good ending to that story :lol:


I never really found a kit to flush my block of contaminants that worked well, its cheaper and eaiser (for me) to just jam a hose down the radiator hoses and take out the t-stat

I have a pressure relief caps on all/most of my cars, never had a problem with it. I think there is a o-ring somewhere in there. Try swapping the cap off the 4.0 jeep to the SD jeep and see if the 4.0 starts losing water.
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ecomike
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#26

Post by ecomike »

Well after extensive tests with non pressure relief and pressure relief lever style radiator caps, I have decided it is not the radiator or the caps or the overflow bottle or the hose.

I have noted that if I relieve the cap pressure slowly using the lever release, shortly after turning off the engine, that it releases lots of gas (and some coolant) from the radiator. Then if I close the lever once the pressure is gone and wait over night about 75 to 85% of the coolant returns to the radiator. Other wise only 10 to 30% returns, if any overnight.

I am begining to think that the water pump is drawing air in at freeway top end operation, (lets call it WOT with the A/C running and the engine good and hot). I think Al was right, the water pump seal is sucking air, but it acts like it is sucking the air at top end operation only max highway speed, 5th gear & WOT, with A/C on high, based on my test results. This seems even more bizzare than a pump seal leaking during the cool down stage, but perhaps one of you has seen this before? This has been going on for years now, and I have changed all the hoses, etc, everything but the water pump, so I am leaning towards Al's conclusion, except that it seems to be doing it during cool down and while the engine is running and at higher RPMs.

I ran it at Idle in the driveway with the A/C on max and the doors wide open for 3 hours yesterday, and a new 16 lb lever cap (Been using 13 lb. caps) held the pressure and nothing flowed into the overflow bottle the whole time. Engine never got over 170 F.

I was working on the A/C and discovered the prior owner never hooked up the A/C blend door vacuum valve controls to the SD22 vacuum pump! I found and fixed that and now on max A/C it will freeze your Bxxxs off (with R-134a!), and the engine-radiator-condensor with the added pusher fan now never gets over 190 F, at 95 F ambient!

One other item I am noticing. Seems that I have little power or reserve power between 50% and 100% WOT, once I am up to about 65 to 70 mphs, with the A/C running, 3 occupants on board a 4500 lb jeep + say 600 lb of people and tools). I have power-response in fourth gear all the way to WOT with all that load but not in fifth gear past 50% WOT. I also notice with all that load, that I can run a few MPHs faster in fourth gear than in fifth gear with all that load, but the engine and transmission RPMs are a bit higher than I like. If I switch to 5th gear and floor it, I really don't get a signifcant response between 50% and 100% WOT, but the engine does run hotter if I maintain WOT for say 5 minutes. I am thinking it is running leaner and making it run hotter and thinking I may need to readjust the smoke screw setting slightly. Just thinking outload. MY SD22 currently does not smoke even at WOT under heavy load.

With A/C off, and only me on board fifth gear has plenty of response all the way to 100% WOT and I think I am gettijng up to about 75 mphs with the Jeep rear end I have.

I am thinking the fifth gear is just too much with all that load.

I bought all the goodies to replace the water pump and intake and exhaust manifold gaskets, but have not had an opportunity to do it yet. Got to get the A/C up and running on the other DD first and the hot rainy...flooding season has already arrived, which is not helping my schedule any.

One last note, I discovered that Stant has two style caps that look exactly alike, but the suttle difference is the lack of a return spring on the vent return valve plate. Part number 11330 has the spring and part number 11331 dies not have the spring. Other than that they both are the same size (exactly) 16 lb caps. It finally dawned on me why they have the one with no spring return. It is for closed cooling systems that have a pressure inspection cap on the radiator and that also have a closed system pressure bottle! Got me to thinking if I just grabbed a good pressure bottle from the JY, I could use one of those caps (closed system) and forget my weird water pump.............problem. I must admit it is temping to just try it for a week to see what it does.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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TooManyIdeas
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#27

Post by TooManyIdeas »

ecomike wrote: One other item I am noticing. Seems that I have little power or reserve power between 50% and 100% WOT, once I am up to about 65 to 70 mphs, with the A/C running, 3 occupants on board a 4500 lb jeep + say 600 lb of people and tools). I have power-response in fourth gear all the way to WOT with all that load but not in fifth gear past 50% WOT. I also notice with all that load, that I can run a few MPHs faster in fourth gear than in fifth gear with all that load, but the engine and transmission RPMs are a bit higher than I like. If I switch to 5th gear and floor it, I really don't get a signifcant response between 50% and 100% WOT, but the engine does run hoter if I maintain WOT for say 5 minutes. I am thinking it is running leaner and making it run hotter and thinking I may need to readjust the smoke screw setting slightly. Just thinking outload. MY SD22 currently does not smoke even at WOT under heavy load.
I've been having the close to the same power problem you have (but in a 720 and no A/C) I've found that I have no throttle responce whatsoever after 3/4 push. Also, I've noticed a little black smoke coming up to speed from 1st to 3rd. 4th and 5th don't smoke at all though. Tell me does you fuel mileage go in the toilet when your on the highway?
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#28

Post by asavage »

ecomike wrote:I am begining to think that the water pump is drawing air in at freeway top end operation, (lets call it WOT with the A/C running and the engine good and hot).
I don't know about that. With ~16 PSI on one side of the seal, I don't think the WP is going to have much luck at sucking in air around the shaft.

It's possible (not likely, but possible) that you are experiencing head gasket leakage only at high load. I had a Subaru come in with that symptom, would only overheat when you put your foot in it for a while, and then it would outgas via the head gasket and blow a bunch of the water out. It was very tricky to diagnose, because no CO in the coolant until you got it good and loaded.
One other item I am noticing. Seems that I have little power or reserve power between 50% and 100% WOT, once I am up to about 65 to 70 mphs, with the A/C running, 3 occupants on board a 4500 lb jeep + say 600 lb of people and tools).
I think 5th is too tall for your application. Simple as that.
I am thinking it is running leaner and making it run hotter . . .
Diesels don't run lean. The old SDs are designed to always have an excess of air. No smoke at WOT is normal for an SD. You do not need to add more fuel until it smokes. If there is an excess of air (more air than needed to oxidize all available fuel), there is not a "too lean" condition like there is in a gasoline engine. The diesel doesn't burn hotter if there is too much air. The resulting EGT is lower, though, which is a Good Thing.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
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ecomike
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#29

Post by ecomike »

Great info, great help, great response, as usual, thanks! If it can't get leaner and thus make it hoter, then that makes it even more unlikely that it is a head gasket leak issue in my case. Sounding more and more like a water pump seal sucking air now. It is not sucking air with the 16 lb cap on it, only with the 13 lb cap, and it is probably only sucking the air in at say up 5 lbs before it gets hot and before the pressure gets up to 13 lbs!

I have been hoping it is not a head gasket leak. It has been like this for 4 years, and 20,000 plus miles, so I doubt it is a head gasket leak.
asavage wrote:
ecomike wrote:I am begining to think that the water pump is drawing air in at freeway top end operation, (lets call it WOT with the A/C running and the engine good and hot).
I don't know about that. With ~16 PSI on one side of the seal, I don't think the WP is going to have much luck at sucking in air around the shaft.

It's possible (not likely, but possible) that you are experiencing head gasket leakage only at high load. I had a Subaru come in with that symptom, would only overheat when you put your foot in it for a while, and then it would outgas via the head gasket and blow a bunch of the water out. It was very tricky to diagnose, because no CO in the coolant until you got it good and loaded.
One other item I am noticing. Seems that I have little power or reserve power between 50% and 100% WOT, once I am up to about 65 to 70 mphs, with the A/C running, 3 occupants on board a 4500 lb jeep + say 600 lb of people and tools).
I think 5th is too tall for your application. Simple as that.
I am thinking it is running leaner and making it run hotter . . .
Diesels don't run lean. The old SDs are designed to always have an excess of air. No smoke at WOT is normal for an SD. You do not need to add more fuel until it smokes. If there is an excess of air (more air than needed to oxidize all available fuel), there is not a "too lean" condition like there is in a gasoline engine. The diesel doesn't burn hotter if there is too much air. The resulting EGT is lower, though, which is a Good Thing.
Just had a last minute thought. If the water pump seal is sucking air in during the cool down cycle over night that air is ending up where? Definately not at the top of the radiator tank! It takes the next engine start up and run for air to circulate and get past the thermostat to reach the radiator!!!! Thus it does not show up in the radiator until after the next start, run, warm up heat up cycle to open the thermostat operation!!!! While that is happening it is creating pressure and increasing volume as the air heats up and pushing some coolant out of the radiator and into the overflow bottle.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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ecomike
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#30

Post by ecomike »

TooManyIdeas wrote:
I've been having close to the same power problem you have (but in a 720 and no A/C) I've found that I have no throttle responce whatsoever after 3/4 push. Also, I've noticed a little black smoke coming up to speed from 1st to 3rd. 4th and 5th don't smoke at all though. Tell me does you fuel mileage go in the toilet when your on the highway?
Mileage is just fine. I get no smoke at all, all the time, currently. You might want to replace the leather diaphram in the pneumatic governor of the IP. Philip noted that his got a little stiff (wrong lube used on it and it dried up and lost its flexibility) after a few months (It was new one too) but that after replacing it his throttle response in all gears improved!

I think my throttle response problem is strictly to much load for 5th gear. I also think 5th gear is not a power gear, but a fuel saving coasting gear. My problem is when I hit the frequent overpasses every 2 blocks on the freeway in Houston, I might as well stay in 4th gear at about 50 to 55 mph to avoid downshifting every 30 to 60 seconds. The probelm is too avoid getting run over by the maniacs on the freeway. Of course if I just drive in rush hour traffic I can play around in first and second gear all the way home, problem solved, LOL.
Regards,

Mike

1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
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