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I have an issue and a theory.
The car is an -92 Ford scorpio 2.9 v6 and the complaint is low heat both in the car and at the gauge, the owner had already
bought a new thermostat and asked me to install it, so i thougt its no big deal...and love and behold it was nothing wrong with the old one, well i installed the new one and as i suspected the issue is still there, no heat!
She told me that its was wery good heat before and about a mounth ago it just happend, now its winter here in sweden and its 5 degrees F -15 c but the issue happend just 1 mounth ago and it was equally cold then and the car dosent warm up properly even inside my 77 degrees garage. The radiatorfan is a beltdriven "wiskos"-type (spell on that please) and its nothing wrong with it.
Now my hypothesis is a lean fuelmixture, i remember days ago when i had a mazda 323 carburator and start to fiddel with the carb and the same sympton appeard.
I suspect the fuelregulator because i did not get any response from the enginge when i disconected the vacuumhose, iam going to check this again with a fuelpressuregauge.
But can a lean or fat mixture cause this symptom or what is going on here? And yes the engine are running rough at idle.
You really need to check the actual running coolant temperature of the engine, at the engine side of the thermostat or the by-pass (heater) hose.
Fords since the 1970s run a continuous flow of coolant through the heater matrix, inside temperature is controlled by blending hot and cold air. Low heater output with a good thermostat is usually down to either the water side of the heater being blocked or the heater air blending flap not moving. You should be able to hear the air blending flap move when you change the heater temperature setting.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
One thing that has a major effect on heater output and engine warm up time is antifreeze concentration, if the concentration is too high the coolant takes longer to reach working temperature, and because the viscosity is considerably higher flow through the heater is reduced and the actual heat transfer efficiency from the coolant to the metal of the heater matrix is reduced is reduced. If the car is running 60/40 antifreeze/water concentration the heater ouput will be lower than if it is running 40/60. 40% solution should protect down to -25c
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Thanks for the tips so far. but it is not just the inside-temp, it is the engine who dosent warm up, i use the tempgauge as a "witness" when the inside-temp drop so do the engine. If i warm it up inside the garage as far as it can be warmed up and after i take a spin i can littery grab every hose in the enginebay and put my hand on the block whitout burn my hand.
Over the phone i asked the owner to turn on the ignition and wait 2 min and guess what... a very long cranktime.
i suspect that the regulator is stuck open. Now my original question, can a lean fuelmixture cause this? i belive it can, whats your thoughts?
One way to look at it any thermostat you buy for one of these could have being lying on a shelf for 20 or 30 years so the odds of finding a faulty one are quite high,
As to lean mixture a lean mixture makes an engine run hot --
Lean mixture = Slower combustion = More waste heat rejected to cooling system and exhaust.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Last edit: 7 years 10 months ago by Andy.MacFadyen.
yes thats one possibility except that it was nothing wrong with the old one.
Well there are more to that exept high temperature, it depends on the load and rpm the enginge running at, lean mixture lower the combustionspeed and temp do to lack of energy but the exhaustgastemp are increases
according to a Swedish expert.
Well i guess iam going to find out, i know for a fact that the thermostat is good, the only thing thats wrong that i found so far its a stuck fuelpressure-regulator, and thats was my guess from the start...a fuelmixture problem.
Andy.MacFadyen wrote: One thing that has a major effect on heater output and engine warm up time is antifreeze concentration, if the concentration is too high the coolant takes longer to reach working temperature, and because the viscosity is considerably higher flow through the heater is reduced and the actual heat transfer efficiency from the coolant to the metal of the heater matrix is reduced is reduced. If the car is running 60/40 antifreeze/water concentration the heater ouput will be lower than if it is running 40/60. 40% solution should protect down to -25c
Thanks Andy! I was unaware of the effect of coolant concentration on heat!
Like any said, lean mixtures burn hot. I've heard of people running bigger jets in snowmobile engines to help keep engine temperature down, but i have never heard of a rich mixture on a car engine effecting the warm up time or heater output.
Andy.MacFadyen wrote: One thing that has a major effect on heater output and engine warm up time is antifreeze concentration, if the concentration is too high the coolant takes longer to reach working temperature, and because the viscosity is considerably higher flow through the heater is reduced and the actual heat transfer efficiency from the coolant to the metal of the heater matrix is reduced is reduced. If the car is running 60/40 antifreeze/water concentration the heater ouput will be lower than if it is running 40/60. 40% solution should protect down to -25c
Thanks Andy! I was unaware of the effect of coolant concentration on heat!
Like any said, lean mixtures burn hot. I've heard of people running bigger jets in snowmobile engines to help keep engine temperature down, but i have never heard of a rich mixture on a car engine effecting the warm up time or heater output.
yes the coolent is one thing i am going to check. Not rich but lean mixture. It happend to me on a mazda with a carb, At the time i didnt know what i was doing when i fiddel with it and the heat just went away, then i sqrewed back the screw and back was the heat again.
And then i found that the regulator on this ford is stuck open.
But who knows it can be a coincidence that the regulator failed approximately at the same time the owner added concentrated antifreeze, the owner do know jack shit about cars so.
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