Problem to solve - overheating - Toyota RAV4 Forums
4.1 General Discuss anything RAV4.1 related that doesn't fit in the categories below.

User Tag List

Reply
 
LinkBack Thread Tools
post #1 of 22 (permalink) Old 04-23-2019, 09:28 PM Thread Starter
Junior Member
Country: jamguy's Flag is: United States
 
Join Date: Aug 2016
Location: Georgia, USA
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thanks: 0
Thanked 10 Times in 9 Posts
(Thread Starter)
Problem to solve - overheating

Filled up my 97 Rav4 today at a Costco. Had no problem for the whole day but in the evening, the engine started misfiring suddenly. The "check engine" light did not come on but I noticed when I limped home that the engine was running hot (could hear the coolant boiling), but the gauge was reading normal. Will take it to my mechanic about 25 miles away. He's the only one that works on my car. Hopefully I wont shut off on the road and need a tow (not a crisis as I have AAA). The car is 10K miles short of a timing belt change, and the fan belt seems OK. Hope it is something that they can diagnose quickly so that my "baby" will be OK. Just hoping it's nothing serious. Thought I'd throw it out there for you guys to mull over. Will let you know the result.
jamguy is offline  
The Following User Says Thank You to jamguy For This Useful Post:
Elle_Rav4 (04-24-2019)
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 04-23-2019, 11:00 PM
Advanced Member
Country: Dr. Dyno's Flag is: United States
 
Join Date: Jan 2010
Location: Eastern CT
Posts: 8,841
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1214 Post(s)
Thanks: 634
Thanked 1,027 Times in 900 Posts
DO NOT try to drive it since you'll likely ruin it if you haven't already. Have it towed. I'm quite sure your mechanic would agree.

Fred
2006 RAV4 V6 4WD Barcelona Red Limited - wife's
2018 Accord Hybrid, Blue Pearl - Dr. Dyno's - 47/47 mpg
2003 Odyssey V6 - handy people & cargo mover
1999 F-250 4X4 Diesel - snow plow, Bully Dog chip
2003 F-250 4X4 - eventual replacement for the '99
2001 F-250 4X4 Diesel - truck camper, TS chip, 20' bike/trike dyno trailer
2004 Suzuki DRZ-400S Dual Sport
1968 Volvo 1800S

It's the pedal (or the handgrip) on the right!!


"If you really believe you get what you pay for there's no such thing as a good deal."
Dr. Dyno is offline  
The Following User Says Thank You to Dr. Dyno For This Useful Post:
Elle_Rav4 (04-24-2019)
post #3 of 22 (permalink) Old 04-24-2019, 01:29 AM
Senior Member
Country: demoder's Flag is: United States
 
Join Date: Jun 2012
Location: USA
Posts: 323
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Thanks: 54
Thanked 160 Times in 104 Posts
Listen to Dr Dyno, and have it towed!! Don't even take the chance.

Hopefully what you heard was air bubbles in the system. Hopefully the misfiring was just oil on the plugs, which is easily fixed by a spark plug tube re-seal. But if she really was overheating, then you could have some big issues, and you don't want to make anything worse by over-heating her again.

Overheat these little engines and you can very quickly be looking at a blown head gasket, which isn't the end of the world, but it gets very expensive very quickly.

Please let us know what your mechanic finds!
demoder is offline  
The Following User Says Thank You to demoder For This Useful Post:
Elle_Rav4 (04-24-2019)
 
post #4 of 22 (permalink) Old 04-24-2019, 07:52 AM Thread Starter
Junior Member
Country: jamguy's Flag is: United States
 
Join Date: Aug 2016
Location: Georgia, USA
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thanks: 0
Thanked 10 Times in 9 Posts
(Thread Starter)
I will. Hopefully it will be OK. Don't really want to buy a newer car as I like a manual transmission and they are almost impossible to find in any model I like.
jamguy is offline  
The Following User Says Thank You to jamguy For This Useful Post:
Elle_Rav4 (04-24-2019)
post #5 of 22 (permalink) Old 04-24-2019, 11:21 AM
Advanced Member
Country: eodgator's Flag is: United States
 
eodgator's Avatar
 
Join Date: Nov 2013
Location: Florida, USA
Posts: 1,892
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 228 Post(s)
Thanks: 729
Thanked 387 Times in 327 Posts
Garage
It sounds like the Engine Coolant Temperature Sensor (ECT) is going out.

Engine Coolant Temperature Sensor (ECT)
Like humans, a vehicle needs to maintain a specific temperature in order to function properly. Too cold, and the vehicle will drink too much petrol. Too hot and the head gasket could leak. Coolant is a liquid used in the vehicles radiator of the car to maintain the temperature at which the engine can perform at its optimum.
The engine coolant temperature sensor simply tells the car's computer (ECM) the current temperature of the vehicle. When the temperature of the coolant reaches between 75 and 95 degrees (depending on the manufacturer specifications), the ECM instructs the radiator fan to turn on and start cooling down the liquid.
Usually it is located either on the bottom of the radiator, or by follow the top radiator hose towards the engine block. You'll see it on mounted on the engine block.
It can be cleaned using a wire brush when you entirely change your engine coolant (approx. every 80,000 km or 50,000 miles).
Symptoms of a Bad or Failing Coolant Temperature Switch (Sensor) Common signs include poor fuel economy, black smoke coming from the engine, engine overheating, and the Check Engine Light turning on. On the RAV4.1 it can prevent the engine from starting.

Easy fix and doesn't require a mechanic. You simply remove the old sensor and install the new one, It's even easy to get to.

See this link Engine Coolant Temperature Sensor Failure


It may be that my sole purpose in life is simply to serve as a warning to others.

RAV4.1, 1999 RAV4, 3S-FE engine, E250F transaxle 5sp AWD, 5 door, LHD, Redneck Edition (RNE), Mossy Oak Obsession wrap, heavily modded, TOAD
'96 Newmar Mountain Aire, 40' diesel pusher motorhome, the mothership
eodgator is offline  
The Following User Says Thank You to eodgator For This Useful Post:
Elle_Rav4 (04-24-2019)
post #6 of 22 (permalink) Old 04-24-2019, 01:48 PM Thread Starter
Junior Member
Country: jamguy's Flag is: United States
 
Join Date: Aug 2016
Location: Georgia, USA
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thanks: 0
Thanked 10 Times in 9 Posts
(Thread Starter)
Thanks for all the advice. Turned out that the plugs, rotor cap, coils and wires needed to be replaced. Also replaced the Coolant Temperature Sensor as per Edogator's advice. I don't think the old one was working properly since the coolant level was low even in the absence of any leaks. The mechanic tested the sytem for leaks and found none. Took the opportunity to do an oil change too. So everything seems to be back on track, running great. I think there's a lot of life left in her!
jamguy is offline  
The Following 2 Users Say Thank You to jamguy For This Useful Post:
Elle_Rav4 (04-24-2019), eodgator (04-24-2019)
post #7 of 22 (permalink) Old 04-24-2019, 03:12 PM
Advanced Member
Country: LugNut's Flag is: United States
 
LugNut's Avatar
 
Join Date: Feb 2005
Location: USA
Posts: 829
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 84 Post(s)
Thanks: 0
Thanked 72 Times in 67 Posts
Check the cooling fan too, with the engine running. Test #1 : Activate the A/C, radiator fan should run on high. Test #2 : With the engine hot, the fan should either run continously or cycle on/off.


Also check the upstream side of the radiator/condensor for too many dead bugs, dustbunnies, etc.


If still a problem (hopefully already solved, but ...), water pump and thermostat would be next on my list. They should get done while doing the timing belt too.

-----------
LugNut
2000 RAV4.1 L, rare Special Edition w/ Leather, AWD
All stock except stereo system, subwoofer, dash cam,
turbo exhaust, outdoor air temp gauge, louder horns, extra ground wire
LugNut is offline  
The Following User Says Thank You to LugNut For This Useful Post:
Elle_Rav4 (04-24-2019)
post #8 of 22 (permalink) Old 04-24-2019, 03:27 PM Thread Starter
Junior Member
Country: jamguy's Flag is: United States
 
Join Date: Aug 2016
Location: Georgia, USA
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thanks: 0
Thanked 10 Times in 9 Posts
(Thread Starter)
The mechanic did the fan test you describe. When I get the timing belt replaced in another 8-10K miles (246K), I'll replace the other two items you mention at that time.
jamguy is offline  
The Following User Says Thank You to jamguy For This Useful Post:
Elle_Rav4 (04-24-2019)
post #9 of 22 (permalink) Old 04-24-2019, 08:23 PM Thread Starter
Junior Member
Country: jamguy's Flag is: United States
 
Join Date: Aug 2016
Location: Georgia, USA
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thanks: 0
Thanked 10 Times in 9 Posts
(Thread Starter)
I also repeated the fan test. I notice only one of the fans cycle on and off. Don't know if this is important but wil let the mechanic know. He advised me to watch the coolant level over the next few days to see if it changes. The funny thing is that the engine feels like it's running hot but the gauge is showing normal despite the fact that the ECT was changed.
jamguy is offline  
post #10 of 22 (permalink) Old 04-24-2019, 10:17 PM
Senior Member
Country: Elle_Rav4's Flag is: United States
 
Elle_Rav4's Avatar
 
Join Date: Aug 2018
Location: Southwest
Posts: 291
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Thanks: 573
Thanked 135 Times in 108 Posts
The ECT sends a signal to the engine computer that adjusts fuel ignition, timing, open loop and closed loop operation, et cetera. It does not cause the coolant temperature to change, at least not directly. Coolant temperature is for the thermostat and fan switch to control. The temperature gage reading on your instrument cluster gets its signal from the (one wire) water temperature sending (WTS) unit located right next to the (two wire) ECT sensor. See picture at http://hele.foute.info/rav4.1/ect.and.wts.jpeg . I would be surprised if the temperature gage was not reading correctly.

Here is the cooling fan circuit: https://www.rav4world.com/forums/mem...an-circuit.jpg . A description of how the circuit works follows. If the fans are switching on and off in a strange manner, from reading here I would wonder if the a/c pressure switch was on its last legs. If you can identify which fan seems to be cycling, this might be helpful.

From member Eodgator and the service manual:

LOW SPEED OPERATION
When the ignition switch is turned on and the a/c is activated, current flows from the mg/c relay (point side) -> the fan no. 3 Relay (coil side) -> GROUND, and the FAN no. 3 Relay is turned on. As a result, current from the CDS FAN fuse flows to terminal 2 of the a/c condenser fan motor -> terminal 1 -> the FAN no. 2 Relay (point side) -> the FAN no. 3 Relay (point side) -> terminal 2 of the radiator fan motor -> terminal 1 -> ground, and both of the fan motors, with the result that the fans are activated at low speed.
If the engine coolant temperature is approx. 90C (194F) or less, and the refrigerant pressure is approx. 15.5 Kg/cm2 (1323 kpa, 191.7 psi) or less, both the a/c water temp. Sw and the a/c single pressure sw are closed, so that the FAN no. 1 Relay and the FAN no. 2 Relay are turned on. As a result, both of the fan motor operate at low speed.

HIGH SPEED OPERATION
When, during a/c operation, the refrigerant pressure becomes higher than ordinary level (approx. 15.5 Kg/cm2 (1323 psi. 191.7 Kpa)), the a/c single pressure sw is turned off. As a result, the FAN no. 1 Relay and the FAN no. 2 Relay are turned off, and the current flows from the RDI FAN fuse to FAN no. 1 Relay (point side) -> terminal 2 of the radiator fan motor -> terminal 1 -> ground, and current from the CDS FAN fuse flows to terminal 2 of the a/c condenser fan motor -> terminal 1 -> the FAN no. 2 Relay (point side) -> ground, and to both of the fan motors in parallel, thus causing the fan motors to operate at high speed.

Note that, because the current flows in the same manner even if the coolant temperature is approx. 90C (194F) or higher, the fan motors still operate at high speed.

1998 Rav4, Manual Transmission, 2WD, JDM engine with 85k miles in early 2019
Elle_Rav4 is offline  
Sponsored Links
Advertisement
 
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



  Similar Threads
Thread Thread Starter Forum Replies Last Post
Problem starting ladysilver 4.2 Faults & Fixes 2 03-05-2019 06:22 PM
AC Problem That Defies Logic ravgogo 4.3 Mechanical 11 08-13-2018 12:32 PM
Yet another overheating thread........ Sinner 4.1 Faults & Fixes 2 10-09-2017 10:48 AM
how to solve ABS, BRAKE, VSC light mara.chiamaia 4.3 Mechanical 3 05-14-2017 12:56 PM
Ignition barrel problem mudinuri 4.1 Faults & Fixes 5 11-15-2015 04:11 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome