Water Dog
Well-known member
zzyzx said:
Tom, I know you don't have the Allegro any longer, but if you ever have the same issue, the temp up when idling and coming down when moving is a very common symptom of a fan clutch.
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Tom, I know you don't have the Allegro any longer, but if you ever have the same issue, the temp up when idling and coming down when moving is a very common symptom of a fan clutch.
SeilerBird
Well-known member
It was not a fan clutch problem. I heard that from a few different sources. The fan clutch passed all the tests perfectly and worked just as it should. The engine is not suppose to get hot enough at idle for the fan clutch to engage. The fan clutch doesn't cause problems it is there in case there is a problem.Water Dog said:
S
ShastaLake
Guest
Water Dog said:
I agree....
A fan clutch is as reliable as any other component on a vehicle, yet sometimes they fail. A common symptom of fan clutch failure is overheating at idle or in heavy traffic. Bad fan clutches can also cause poor performance of the car's air conditioning system because the fan also cools the air conditioner's condenser, which is directly in front of the radiator. A fan clutch can also fail in a stuck on position where engine power is lost even when the fan is not necessary. This type of failure can also decrease fuel economy.
ranger magnum
Well-known member
Getting ready for our annual desert trip. I flushed the radiator, installed the fans, oil cooler and two quart oil filter. Im running 50/50 water to coolant, and water wetter.
I decided against an aux radiator, as i could not find a suitable unit.
What i decided to was install a misting system to cool the radiator. I read that tour bus companies that run from vegas to Los Angeles during the summer have employed this technique.
I ran a water line from my fresh water tank to a windsheild washer pump. From there i installed four misters mounted to aluminum brackets that spray water on the radiator. In effect it is a swamp cooler for the engine. My hope is that it does two things: the water cools the air passing through the radiator, and the water that hits the radiator carries the heat away.
When i get back I am going to install a 5 row radiator in the hopes of running constsnt 220 degrees
I decided against an aux radiator, as i could not find a suitable unit.
What i decided to was install a misting system to cool the radiator. I read that tour bus companies that run from vegas to Los Angeles during the summer have employed this technique.
I ran a water line from my fresh water tank to a windsheild washer pump. From there i installed four misters mounted to aluminum brackets that spray water on the radiator. In effect it is a swamp cooler for the engine. My hope is that it does two things: the water cools the air passing through the radiator, and the water that hits the radiator carries the heat away.
When i get back I am going to install a 5 row radiator in the hopes of running constsnt 220 degrees
ranger magnum
Well-known member
Well, its been a while, but I solved my hot running condition... Turns out it was a clogged radiator. Replaced it with a 5 row extra heavy duty unit, and now it never gets hotter than
udidwht
Well-known member
For P30 owners:
The stock T-stat is 195F. That means it will start to open at 195F degrees. Has nothing to do with what temperature the engine will run at. Going to a cooler T-stat will not allow the engine to run cooler. That is a huge myth. It will only delay how long it takes for the engine to warm up to what the manufacturer wanted the engine to operate at. This will actually increase wear overtime.
A 454 in an RV will run warmer than the same engine in a pick-up or car. How warm? That depends on timing, how well maintained the cooling system has been primarily. The clutch fan is calibrated to cycle on/off on a 90F degree day between high & low. Think of it as a 2 speed fan. The coil on the front of the clutch fan begins to engage at approximately 150 degrees radiator discharge air temp. That will very likely mean the engine temp will be at roughly 230+ before it fully engages (loud roar). This almost always requires a decent grade pull to acquire. Unless it a 90F degree day you likely won't hear the P-51 roar.
The dash gauge (temp) are not very accurate and generally will read higher than the real engine temp. If you suspect the gauge is reading high use an IR temp gun and monitor the T-stat housing and lower radiator hose temps. But remember the dash gauge gets it read from near the head on later (late 80-early 90+) 454 engines and that temp will on average be 20-30 degrees higher than the radiator inlet temp.
Do your IR reads while driving. On a 60-70F degree day or so you should see readings of 185-200 or so while driving (T-stat housing) Once in traffic or idling they will creep up to 205-210+. The lower hose you'll have to get out after a highway run and check it rather quickly. But with a decent running cooling system it it should be 30+ degrees or so cooler than the inlet temp. Again checking the hose/s after a grade pll or heavy traffic will yield a narrower result between the inlet/outlet temps.
When checking the clutch fan use your hand to spin the fan (engine off cold) it should not spin very much at all if you attempt to fling the fan blade. Anther method (be very careful) use a tightly rolled up magazine and carefully attempt to stop the fan with the engine idling (warm). If the fan stops easily you need to replace it. Another method: When the engine is at operating temp stop watch the fan while turning off the engine. It should stop rather quickly with the engine. If the engine stops but the fan keeps free wheeling it needs replacing.
Id also be very reluctant to add fans or water spray to the stock set up. Why? Doing so will likely prevent the clutch fan from kicking in when it needs to kick in. Nothing moves air like a mechanical clutch fan. The coil on the front of the clutch fan needs the proper discharge air temp to work correctly.
The stock T-stat is 195F. That means it will start to open at 195F degrees. Has nothing to do with what temperature the engine will run at. Going to a cooler T-stat will not allow the engine to run cooler. That is a huge myth. It will only delay how long it takes for the engine to warm up to what the manufacturer wanted the engine to operate at. This will actually increase wear overtime.
A 454 in an RV will run warmer than the same engine in a pick-up or car. How warm? That depends on timing, how well maintained the cooling system has been primarily. The clutch fan is calibrated to cycle on/off on a 90F degree day between high & low. Think of it as a 2 speed fan. The coil on the front of the clutch fan begins to engage at approximately 150 degrees radiator discharge air temp. That will very likely mean the engine temp will be at roughly 230+ before it fully engages (loud roar). This almost always requires a decent grade pull to acquire. Unless it a 90F degree day you likely won't hear the P-51 roar.
The dash gauge (temp) are not very accurate and generally will read higher than the real engine temp. If you suspect the gauge is reading high use an IR temp gun and monitor the T-stat housing and lower radiator hose temps. But remember the dash gauge gets it read from near the head on later (late 80-early 90+) 454 engines and that temp will on average be 20-30 degrees higher than the radiator inlet temp.
Do your IR reads while driving. On a 60-70F degree day or so you should see readings of 185-200 or so while driving (T-stat housing) Once in traffic or idling they will creep up to 205-210+. The lower hose you'll have to get out after a highway run and check it rather quickly. But with a decent running cooling system it it should be 30+ degrees or so cooler than the inlet temp. Again checking the hose/s after a grade pll or heavy traffic will yield a narrower result between the inlet/outlet temps.
When checking the clutch fan use your hand to spin the fan (engine off cold) it should not spin very much at all if you attempt to fling the fan blade. Anther method (be very careful) use a tightly rolled up magazine and carefully attempt to stop the fan with the engine idling (warm). If the fan stops easily you need to replace it. Another method: When the engine is at operating temp stop watch the fan while turning off the engine. It should stop rather quickly with the engine. If the engine stops but the fan keeps free wheeling it needs replacing.
Id also be very reluctant to add fans or water spray to the stock set up. Why? Doing so will likely prevent the clutch fan from kicking in when it needs to kick in. Nothing moves air like a mechanical clutch fan. The coil on the front of the clutch fan needs the proper discharge air temp to work correctly.
SeilerBird
Well-known member
Boy this was a real trip reading an old thread of mine. I had completely forgotten about all this stuff.
udidwht
Well-known member
Water Dog said:
Normal behavior.
udidwht
Well-known member
One other thing to add...
Be certain your auxiliary fan is working. It is the fan that sits directly in front of the AC condensor/oil cooler. You're staring at it when the engine hood (front of RV) is open. When this fan fails the engine temp will climb to the red when in traffic. It is designed to come on as follows...
1. When the AC pressure reaches ~225psi
or
2. When the engine temp reaches approximately 221F
It's wired into the passenger side cylinder head temp sensor.
Be certain your auxiliary fan is working. It is the fan that sits directly in front of the AC condensor/oil cooler. You're staring at it when the engine hood (front of RV) is open. When this fan fails the engine temp will climb to the red when in traffic. It is designed to come on as follows...
1. When the AC pressure reaches ~225psi
or
2. When the engine temp reaches approximately 221F
It's wired into the passenger side cylinder head temp sensor.
SeilerBird
Well-known member
Thanks for the info but I now live in a permanently parked fifth wheel with no engine.
Tapemeasureman
Member
Hhhmmm, SOME of us are still having this issue in the here and now . Ive replaced the fan clutch, dropped to a 180 thermostat, corrected a tiny leak at the thermostat housing from a stripped out bolt hole. Next on my agenda will be to try a fin comb, drain the rad, wash out the rad, check prices on new, and used rads, and rad reaming for my '92 Damon, while it hasnt boiled over since driving home from purchasing it. It runs perilously hot, 30 or 40 degrees too hot and Im sure led to the pre mature failure of the trans. Ill also be looking at the ignition timing. From everything I can tell It should be pretty much straight up and down on 210, or close to it. Ive only had a few Chevys, Fords run 1 temperature, period.
udidwht
Well-known member
On the flats at speed yes a mid 210 reading would be normal. The warmer the ambient temp the further the needle will be to the right of 210. In traffic on a hot day the dash gauge will creep up. You'll also hear the clutch fan kick in at times. Especially more frequent on 90+ degree day (even on the flats). On a lengthy grade (5-8 percent) the clutch fan will keep the temp between 230-237.
Also be certain you're running at min a 50/50 coolant mixture. Preferably no less than 33 percent coolant vs distilled water. Water cools better than coolant.
Also be certain you're running at min a 50/50 coolant mixture. Preferably no less than 33 percent coolant vs distilled water. Water cools better than coolant.
Ex-Calif
Well-known member
Old thread but the 454 in my Georgie Boy runs at like 180-190 all day. The gauge reads high so I shot it with my IR gauge.
I run 20-25% coolant to water because as you said water is a better coolant and have a 190 t/stat.
I climbed from Phoenix to Flagstaff last summer in 100+ temps and while the needle climbed it never got over 220. I checked at the gas stop after the climb as we had more climbing to do to get into Joshua forest and I was concerned.
udidwht
Well-known member
96 you'd have 8.1 Vortec w/Allison trans
One thing I noticed with the early-mid P-32 chassis RVs was the temp gauge on the dash differed in how the increments were shown on various model coaches. On my 1994 P-32 454 TBI the center of the temp gauge is 210 and boil was 260 (50 degree difference). The first gray bar to the right of 210 would end just before the first small red hash which I figure is ~240F. After that final red ash at (260F).
The following links are right after I did my coolant, T-stat (Delco 195F) and hoses (upper, lower and bypass) the IR reading is the temp right at the T-stat housing. The run was from the bottom of a hill (street) with a (1 mile) 6 percent climb at 80-85F. Note the IR readings taken from the same spot on the T-stat housing with the doghouse up once stopped idling vs the dash gauge reading. Crazy eh?
Bottom of hill:
Top of hill:
What I found out was when doing the coolant I inadvertently bought 'concentrated coolant' (70/30) coolant vs water. Will run hotter. So after using distilled water I got the ratio down to approximately 55 percent distilled water vs 45 percent coolant. After that the needle behaved better but still not accurate to say the least. The dash temp gauge on those era RVs is not very accurate at all. They read often times on the high side by as much as 20-40+F degrees. Most often noted on warm days.
The normal operating range for those era chassis was anywhere from 195 - 240F. That comes from a GM tech I know that worked on them for years back then. He told me folks used to complain often about the dash gauge wildly going up-down.
On the flats the dash temp gauge will hang at 210 or slightly to the right (half needle width) when at cruise speed of ~60mph on 80+F degree day. The clutch fan cycles more often the warmer the ambient temp is. On a hot day say 90-100+F at cruise speed (60mph)the temp will be anywhere from 212-218. That is what shows on my ALDL phone app I have which pulls the temp from the ECM which gets the temp from the CTS on front of intake manifold.
GM ran em hot in that era due to smog nazis.
Last edited:
Ex-Calif
Well-known member
>>After that the needle behaved better but still not accurate to say the least. The dash temp gauge on those era RVs is not very accurate at all. They read often times on the high side by as much as 20-40+F degrees. Most often noted on warm days.<<
Mine reads almost exactly like yours. 20+ degrees high.
I run 30% prestone 70% water.
Mine reads almost exactly like yours. 20+ degrees high.
I run 30% prestone 70% water.
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