95 Camry 2.2 - Blown Head Gasket?
#12
04-23-2013, 07:13 AM
An update was promised, and here it is....
The K&W Head Gasket and Block Repair liquid seems to have done something, as there is no white smoke and a second block test indicates no combustion leak.... However, the engine is overheating within about 15 minutes of start-up. Gasses are seen coming from the radiator cap area, and the engine begins to idle roughly (300-400 rpms, about half of normal). After cool-down, the engine works fine again, but only for a short period of time before reoccurrence.... Note: Just after completing the follow-up block test, some coolant even forced its' way back out the radiator fill port (exhaust gases?).
1) I replaced the thermostat with a "failsafe" product (stays open in event of malfunction; hopefully installed properly), but no improvement noted; 2) I checked the upper radiator hose for pressure (squeeze, then release, to trooubleshoot the water pump) but everything seemed normal; the lower hose is not cold, further suggesting that the system is flowing...; 3) The radiator is less than 2 years old, and it has sufficient coolant in it; 4) The radiator fans are in normal working order. There continues to be no fluid leakage on the ground, and no "milkiness" in the oil....
Is it possible the previously assumed "coolant leak" has been caused solely by the engine overheating? Is something like a faulty radiator cap a potential cause? Or is it looking more and more like the elusive signs of a head gasket problem?
As always, your thoughts are appreciated.
The K&W Head Gasket and Block Repair liquid seems to have done something, as there is no white smoke and a second block test indicates no combustion leak.... However, the engine is overheating within about 15 minutes of start-up. Gasses are seen coming from the radiator cap area, and the engine begins to idle roughly (300-400 rpms, about half of normal). After cool-down, the engine works fine again, but only for a short period of time before reoccurrence.... Note: Just after completing the follow-up block test, some coolant even forced its' way back out the radiator fill port (exhaust gases?).
1) I replaced the thermostat with a "failsafe" product (stays open in event of malfunction; hopefully installed properly), but no improvement noted; 2) I checked the upper radiator hose for pressure (squeeze, then release, to trooubleshoot the water pump) but everything seemed normal; the lower hose is not cold, further suggesting that the system is flowing...; 3) The radiator is less than 2 years old, and it has sufficient coolant in it; 4) The radiator fans are in normal working order. There continues to be no fluid leakage on the ground, and no "milkiness" in the oil....
Is it possible the previously assumed "coolant leak" has been caused solely by the engine overheating? Is something like a faulty radiator cap a potential cause? Or is it looking more and more like the elusive signs of a head gasket problem?
As always, your thoughts are appreciated.
#13
04-23-2013, 11:39 AM
How long did you conduct the new block test,10-15 minutes?
The IAC valve also uses coolant temp to set idle. It has small coolant hoses running to and from it. If the hoses have air in them the idle can become erratic. The idle issue is most likely related to air in the coolant system.
Unless the coolant system including engine were completely drained there would not normally be air in the IAC lines from just a T-stat, radiator or heater core coolant drain.
Fill the radiator slowly! with coolant until full. Make sure the heater is on hot to open the coolant line heater valve. Then squeeze both upper and lower hoses repeatably to get air out and replace by more coolant until no more can be added. If this is done the coolant system should be full enough to prevent overheating at engine after engine start up and idle and erratic idle. There will be some drop in coolant requiring makeup coolant to be added.
The engine should be able to idle indefinitely without overheating. You stated the fans work OK. They should cycle on and off controlled by the temp switch at the bottom of the radiator.
Even if the radiator cap was removed prior to engine warm up, there still should be no overheating or coolant spewing out the radiator fill point. There might be some surge of coolant if you rev the engine.
If you have a thermometer take the coolant temp at the fill port on the radiator, let the engine warm up with radiator cap off. Air may be inside the coolant system but the actual coolant temp could be normal.
You stated the upper and lower hoses are hot? The lower hose may be 20-30 degrees cooler then the top.
When installing the T-stat make sure the hole or giggle pin on the outer flange is oriented up and the spring portion goes into the head.
The radiator cap would need to be installed for normal driving to pressurize the system and raise the boiling point of the coolant. The cap need not be installed to prevent over heating at engine idle. If the engine is overheating at idle then there is an issue with the cooling system or head gasket issue.
You might look more carefully at the radiator, these sealants can plug more things up then head gasket leaks. If you put a garden hose open full into the top of the radiator, water should not back up when running out the bottom.
The IAC valve also uses coolant temp to set idle. It has small coolant hoses running to and from it. If the hoses have air in them the idle can become erratic. The idle issue is most likely related to air in the coolant system.
Unless the coolant system including engine were completely drained there would not normally be air in the IAC lines from just a T-stat, radiator or heater core coolant drain.
Fill the radiator slowly! with coolant until full. Make sure the heater is on hot to open the coolant line heater valve. Then squeeze both upper and lower hoses repeatably to get air out and replace by more coolant until no more can be added. If this is done the coolant system should be full enough to prevent overheating at engine after engine start up and idle and erratic idle. There will be some drop in coolant requiring makeup coolant to be added.
The engine should be able to idle indefinitely without overheating. You stated the fans work OK. They should cycle on and off controlled by the temp switch at the bottom of the radiator.
Even if the radiator cap was removed prior to engine warm up, there still should be no overheating or coolant spewing out the radiator fill point. There might be some surge of coolant if you rev the engine.
If you have a thermometer take the coolant temp at the fill port on the radiator, let the engine warm up with radiator cap off. Air may be inside the coolant system but the actual coolant temp could be normal.
You stated the upper and lower hoses are hot? The lower hose may be 20-30 degrees cooler then the top.
When installing the T-stat make sure the hole or giggle pin on the outer flange is oriented up and the spring portion goes into the head.
The radiator cap would need to be installed for normal driving to pressurize the system and raise the boiling point of the coolant. The cap need not be installed to prevent over heating at engine idle. If the engine is overheating at idle then there is an issue with the cooling system or head gasket issue.
You might look more carefully at the radiator, these sealants can plug more things up then head gasket leaks. If you put a garden hose open full into the top of the radiator, water should not back up when running out the bottom.
Last edited by toyomoho; 04-24-2013 at 10:50 AM.
#14
04-24-2013, 07:58 AM
Air in the coolant system is a definite possibility; I will purge the system today as instructed in your note. The coolant fill will take place with the engine idling as suggested.
The block test was done after the engine was quite warmed up; the block test itself is only for a one minute cycle (holding the liquid-filled chamber on top of the radiator opening, while slowly pumping air through said chamber), if that is what you are referring to.
Other stuff: 1) the spewing coolant was from a fully warmed up engine (maybe even hot); there was no revving of the engine during the test. 2) The upper hose was definitely hotter than the lower hose, as should be. I was just noting that the lower hose was not cold, which would have been symptomatic of a problem with the coolant moving through the system. 3) The T-stat produced by Failsafe does not have a hole/giggle pin on the outer flange; everything is symmetrical; the spring portion is definitely oriended into the head, however. 4) The head/block sealant utillized was mild in comparison to most I have seen advertised, not even requiring a draining of the coolant system; hopefully the radiator was not impacted.
Key questions to be answered next include: Will the purging of air in the coolant system improve the idle issue? Can the engine idle indefinitely without overheating? Will post another update tonight if possible....
Thanks much.
The block test was done after the engine was quite warmed up; the block test itself is only for a one minute cycle (holding the liquid-filled chamber on top of the radiator opening, while slowly pumping air through said chamber), if that is what you are referring to.
Other stuff: 1) the spewing coolant was from a fully warmed up engine (maybe even hot); there was no revving of the engine during the test. 2) The upper hose was definitely hotter than the lower hose, as should be. I was just noting that the lower hose was not cold, which would have been symptomatic of a problem with the coolant moving through the system. 3) The T-stat produced by Failsafe does not have a hole/giggle pin on the outer flange; everything is symmetrical; the spring portion is definitely oriended into the head, however. 4) The head/block sealant utillized was mild in comparison to most I have seen advertised, not even requiring a draining of the coolant system; hopefully the radiator was not impacted.
Key questions to be answered next include: Will the purging of air in the coolant system improve the idle issue? Can the engine idle indefinitely without overheating? Will post another update tonight if possible....
Thanks much.
#15
04-24-2013, 11:17 AM
Might drill a small hole in the flange (perhaps 0.125 inch) of the T-stat then orient the hole in the up position or find a T-stat with a hole or giggle pin. See photo in link below:
http://ts2.mm.bing.net/th?id=H.45958...h=184&c=7&rs=1
This is a vent which aids in getting the air out during filling of the system and any air remaining in the system. Not stating it is the cause but Toyota T-stat do have this vent feature for some reason.
http://ts2.mm.bing.net/th?id=H.45958...h=184&c=7&rs=1
This is a vent which aids in getting the air out during filling of the system and any air remaining in the system. Not stating it is the cause but Toyota T-stat do have this vent feature for some reason.
#16
04-26-2013, 04:33 PM
Well, I swallowed my pride and had a diagnostic done by a pretty knowledgable shop. They say the head gasket is fine, and that the problem is a defective/broken/cracked/leaking heater control valve! There certainly is some green discoloration around that area. Interesting that the Haynes manual doesn't so much as mention the heater valve in their Index, much less ID it as a possible cause for the issues I've been having....
Apparently this plastic part just breaks down/becomes brittle over time, and then fails. A new valve and a set of hoses from Rockauto.com will set me back less than $100. Hope that is the trick that solves this puzzle....
By the way, I did redo the t-stat, drilling a small hole and reinstalling same in the 12 o'clock position.
As always, will keep you posted.
Apparently this plastic part just breaks down/becomes brittle over time, and then fails. A new valve and a set of hoses from Rockauto.com will set me back less than $100. Hope that is the trick that solves this puzzle....
By the way, I did redo the t-stat, drilling a small hole and reinstalling same in the 12 o'clock position.
As always, will keep you posted.
Thread
Thread Starter
Forum
Replies
Last Post
Player
General Tech
6
05-04-2010 06:27 AM
