overheating and water temp gauge fluctuating
08-19-2018, 12:02 PM
#1
overheating and water temp gauge fluctuating
Good Sunday everyone!
Novice here..... Got an 88 F150 XLT Lariat and the oil temp gauge heads to the red side when idling but will move back to the middle again when up to speed. Just recently the water temp gauge started shifting towards the red also.
Possible causes?
Novice here..... Got an 88 F150 XLT Lariat and the oil temp gauge heads to the red side when idling but will move back to the middle again when up to speed. Just recently the water temp gauge started shifting towards the red also.
Possible causes?
08-19-2018, 02:02 PM
#2
I may be wrong but I believe oil pressure gauges are dummy gauges in 88. Basically, if the oil light isn't on, ignore the gauge.
Temp gauge is different and is a cause for concern.
First things first, make sure you have coolant. Check the plastic overflow on the right hand side of the engine bay, there should be a marker for cold fill. If that has coolant in it you should be good(tbh the overflow container is one of those things i'm a bit iffy on my understanding, idk if it goes down when the radiator is drained or not....)but to check the radiator take cap off with the engine off AND THE MOTOR COMPLETELY COOL
Anyway if you're low on coolant you need to find out why, but let's say you're good on coolant.
Possible issues:
Bad thermostat: the thermostat regulates flow of coolant to keep temperature constant. If it jams open your engine can run cold, if it gets stuck shut you essentially have no cooling system cause there's no flow
Bad water pump: The water pump moves coolant through the system. If this goes bad it's usually the bearing or the fins will rust away over time causing poor coolant flow.
Bad fan clutch: This is one of the items i'd really look at. I feel like with many modern cars having electrically controlled fans, many enthusiasts don't even know what this is. Basically, it controls the fan that drags air through the radiator. If the engine starts getting too hot, a bimetal spring will engage the fan and suck more air through the radiator. This usually only happens at low speeds and at red-lights. On the highway, enough air if forced through the radiator so the fan isn't necessary.
If you do find a leak, but have plenty of coolant, the temperature is likely fluctuating due to air in the system. What happens is, as coolant leaks out air takes its place. This air can get trapped and cause the thermostat to function incorrectly causing temperature spikes.
Anyways a temp problem is not something to ignore. If it starts getting high(i'd say 75% of the gauge and up) turn off the motor and pull over. Don't try to drive 2 miles to the next rest stop. Fork up the cash and get it towed. $80 for a tow truck is better than $3,000+ for a new motor or a different truck. AAA or a comparable service is also a good investment.
Temp gauge is different and is a cause for concern.
First things first, make sure you have coolant. Check the plastic overflow on the right hand side of the engine bay, there should be a marker for cold fill. If that has coolant in it you should be good(tbh the overflow container is one of those things i'm a bit iffy on my understanding, idk if it goes down when the radiator is drained or not....)but to check the radiator take cap off with the engine off AND THE MOTOR COMPLETELY COOL
Anyway if you're low on coolant you need to find out why, but let's say you're good on coolant.
Possible issues:
Bad thermostat: the thermostat regulates flow of coolant to keep temperature constant. If it jams open your engine can run cold, if it gets stuck shut you essentially have no cooling system cause there's no flow
Bad water pump: The water pump moves coolant through the system. If this goes bad it's usually the bearing or the fins will rust away over time causing poor coolant flow.
Bad fan clutch: This is one of the items i'd really look at. I feel like with many modern cars having electrically controlled fans, many enthusiasts don't even know what this is. Basically, it controls the fan that drags air through the radiator. If the engine starts getting too hot, a bimetal spring will engage the fan and suck more air through the radiator. This usually only happens at low speeds and at red-lights. On the highway, enough air if forced through the radiator so the fan isn't necessary.
If you do find a leak, but have plenty of coolant, the temperature is likely fluctuating due to air in the system. What happens is, as coolant leaks out air takes its place. This air can get trapped and cause the thermostat to function incorrectly causing temperature spikes.
Anyways a temp problem is not something to ignore. If it starts getting high(i'd say 75% of the gauge and up) turn off the motor and pull over. Don't try to drive 2 miles to the next rest stop. Fork up the cash and get it towed. $80 for a tow truck is better than $3,000+ for a new motor or a different truck. AAA or a comparable service is also a good investment.
Last edited by me1234; 08-19-2018 at 02:10 PM.
08-23-2018, 11:37 AM
#4
Member
Join Date: Jan 2018
Location: Memphis, TN, Earth, Milky Way
Posts: 11,256
Received 1,731 Likes
on
1,487 Posts
Your thread title says "water temp gauge"; your post says "oil temp gauge"; and that reply started off about the oil PRESSURE gauge.
The caption of this diagram describes the FACTORY gauges in these trucks, and the links in the caption explain more about each one:
(phone app link)
The caption of this diagram describes the FACTORY gauges in these trucks, and the links in the caption explain more about each one:
(phone app link)