Where The Devil Is That Coolant Going?
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Postmaster
Joined: Apr 2001
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Where The Devil Is That Coolant Going?
4.0L engine, 221,000 miles, is going through coolant to the tune of 1.5gal monthly. Suspect a head gasket or cracked head.
A forum seach on the topic reveals all sorts of telltale signs but this engine does not display any of the classic symptoms -no milky/cloudy oil or oil in the coolant - no smoke or odors from the exhaust, no leaks under the vehicle.
No rise in the temp. gauge until coolant nearly empty. Heck, it idles fine, runs smoothly and continues to get 18+ mpg at its advanced age.
How could it go through this much coolant without any evidence? If the head gasket were leaking wouldn't there be an accompanying pressurization of the cooling system?
A forum seach on the topic reveals all sorts of telltale signs but this engine does not display any of the classic symptoms -no milky/cloudy oil or oil in the coolant - no smoke or odors from the exhaust, no leaks under the vehicle.
No rise in the temp. gauge until coolant nearly empty. Heck, it idles fine, runs smoothly and continues to get 18+ mpg at its advanced age.
How could it go through this much coolant without any evidence? If the head gasket were leaking wouldn't there be an accompanying pressurization of the cooling system?
Tuned
Joined: Jun 2003
Posts: 295
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From: poughkeepsie ny
Where The Devil Is That Coolant Going?
Did you try pressure testing the coolant system? Many times this will show evidence of a leak in the system. If/ when you do this, make sure to keep pressure up there for ~ 10 mins. Sometimes a leak wont present itself until after some time has passed.
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Joined: Dec 2001
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From: UT
Where The Devil Is That Coolant Going?
I would agree with the pressure test.
You didn't say if your 4.0 is the OHV or not, but a fairly common place for the OHV (esp. '91-'94) to lose coolant is through the lower intake manifold gasket. A common symptom is fouling of the spark plug's (esp. #5) and pinging going uphill on the highway. It can often be fixed by simply tightening the lower intake manifold bolts to spec. They seem to come loose over time.
You didn't say if your 4.0 is the OHV or not, but a fairly common place for the OHV (esp. '91-'94) to lose coolant is through the lower intake manifold gasket. A common symptom is fouling of the spark plug's (esp. #5) and pinging going uphill on the highway. It can often be fixed by simply tightening the lower intake manifold bolts to spec. They seem to come loose over time.
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Postmaster
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Where The Devil Is That Coolant Going?
Thanks Seagull369 and MrShorty for the replies.
I also posted in the HVAC forum and received a similar response re:intake manifold. Since it is a '91, I really pray it is something as simple as loose manifold bolts and not a blown head gasket or cracked head.
Appreciate the quick responses!
I also posted in the HVAC forum and received a similar response re:intake manifold. Since it is a '91, I really pray it is something as simple as loose manifold bolts and not a blown head gasket or cracked head.
Appreciate the quick responses!
