Is it me or am I expecting too much?
I have a 1992 Previa with 299,957 miles that started overheating. My mechanic replaced my water pump and thermostat. The van ran fine for 17 days, about 900 miles and started overheating again: at stop lights, the temp. guage would move up (never reaching the top) and when the light changed and I accelerated, the guage went back to the midpoint. Having recently had the water pump and thermostat replaced, I went back to my mechanic. The diagnoses- blown head gasket. About $3,000 for parts, including a long block, and about $1,500 for labor.
I asked “why do you think it got hot again?” Can’t say, no one knows.
Am I asking too much to ask for the labor to be in the warranty from the previous work and to use the current long block - nott replace it?
Thank you for your responses.
And how did he come to this conclusion?
A few things do not add up.
First, a blown headgasket will typically force much more hot air into the water jacket when you accelerate, so the temp will rise when you accelerate from a stop rather than drop. Dropping as you accelerate is more typical of a nonfunctioning cooling fan.
Second, if you have a bad headgasket he should have been able to tell the first time around. When he was doing the diagnosis he should have seen bulbbles in the radiator fill hole or contamination in the coolant and done a cylinder leak down test.
Did he change the water pump because it was leaking or the flow was low? Were the impellars worn out? Or was he just throwing parts at the problem?
Why would he say you need a whole long block for a bad headgasket insteand of just a new headgasket?
I definitely would have this looked at by another shop, an independently owned and operated one.
Get another opinion. A faulty cooling fan would produce the symptoms you describe.
There are tests to determine whether or not a head gasket has failed. At 300K miles it’s certainly a possibility, but there shouldn’t be any guesswork involved.
If the head gasket had been leaking the water pump and thermostat wouldn’t have made any difference. You said it was fine for 900 miles.
A bad head gasket shouldn’t require a long block. A worn out engine requires a long block. Something doesn’t add up.
Any number of symptoms/problems can arise when a head gasket goes bad. It depends on where and how it fails as well as how the engine is designed. Combustion gases leaking past the gasket and into the cooling system is one failure mode. If this happens, you get a lot of “air” into the cooling system and this can result in air pockets interfering with the normal circulation of coolant. When you accelerate, the water volume increases and it overcomes the air pocket and the temp will go down. There are a number of plausible reasons for this symptom and some have been covered in previous posts.
Another failure mode is coolant leaking into the crankcase and diluting the oil. When this happens, the bearings can get damaged quickly and it makes no sense to just replace a head gasket if this condition has gone unfixed for any length of time.
Mileage and expected lifespan also come into play when considering investing $1500+ on a new head gasket on a tired engine.
You should be asking your mechanic why he feels the long block is necessary. Likely, (s)he has a good reason and may have even explained it to you already. Post back here if you need clarification after speaking with them again.
Your car is worth $500 or less if it’s running properly. As it is, it’s salvage. Time to move on…
I agree at this point. This vehicle lived way past life expentency and is ready for car heaven.
First I’d want to know what’s really wrong. This fits the description of a bad cooling fan more than a bad headgasket. And there’s no way I’d give up on a car that only needed a new cooling fan.
If coolant is being constantly expelled from the radiator overflow tank, and you must remove the radiator cap to add more coolant, it’s the head gasket and it always was the head gasket…
I second the cooling fan diagnosis and the mechanic who did this work should have (assuming he didn’t) verified that the engine got to operating temperature and the fan was operative after doing the work rather than throwing a water pump/thermostat on and running it out the door.
Hold off on the engine replacement at this point. Raise the hood, allow the engine to idle until the temp comes up, and make sure the fan cycles on.
At 18 years and 300k miles it’s entirely possible the fan has simply cashed in its chips.
(And for what it’s worth, a head gasket is one of those things that is frequently misdiagnosed when an overheating complaint occurs.)
every old dog has his day
It could even be a collapsed (internally collapsed) hose.
Vehicles this old are rarely worthwhile owning UNLESS you are a mechanically inclined person with a set of tools, a garage and some spare time. The others here suggest a fan problem, and that’s quite likely. I’d suggest a clogged radiator. If it were my problem, in my driveway, I’d scout out a replacement radiator either from a “recycler” (junk yard) or the internet. A junkyard radiator can be bought with the fans already attached. Then replace the radiator and fan, and sport it up with new hoses, and I bet your problems are over, for the short term.
Long term you are either going to learn to repair your own vehicle, or you are going to junk it. Sears will sell you a box of sockets and tools for between $80 and $200 (which will last you the rest of your life if you don’t lose them), and a service manual for the Previa might cost $20.00 or so. If you totally botch up the job and the van has to be towed to the wrecking yard, you are out almost nothing, because your next vehicle will provide reasons for you to use the tools and you can sell the Previa manual on EBay.
I’m also voting for the cooling fan or the cooling fan switch. If you have two fans, one for the AC, then you can check by turning on the AC next time you are at a stop and the temp starts rising. The fan for the AC will start cooling down the radiator.
If you have only one fan for the radiator, you can check to see if its the fan or the switch by turning on the AC, if the fan comes on, its the switch, if not, its the fan.
I’m changing my vote, I just remembered that the cooling fan switch is designed to fail in the fan on mode on Toyota’s, so it has to be the fan motor or fuse or associated wiring.
Try replacing the radiator cap. I had a similar problem on my 95 Eclipse. There’s a gasket built into the cap that deteriorates over time, allowing coolant to leak out very slowly around the gasket. $7 at an auto parts store for a replacement cap might solve your problem. Might not, but for $7, it can’t hurt.