Sustainobile

Hey y'all! sorry for the long post but i feel it's necessary to explain the issue. I have a 91 yota pickup 4x4 with a recently installed rebuilt 3VZE engine.
It's been a long time since I've been on here but I'm going to start being a frequent user. I just got back from a long trip from San Fran back to Seattle and was having all sorts of issues during my time in San Fran.

Anyway, heres the deal: My temp gauge fluctuates from below halfway to above halfway and 3/4 between C and H after prolonged time driving (2-4 hours). It's on the downhills and easy grades that it'll cool all the way down for a bit. It stays cool until that 2-4 hour mark by the way. Additionally, after the engine warms up, if I shut the truck off, the gauge shows the temp about 3/4 Hot on startup until I get going at which point it cools off quickly. It never did that before. The radiator is of course full of coolant by the way.

leading up to the current issue, A couple months ago I had a rebuilt engine put in(old one had about 235k) and an assortment of new parts including a new radiator and thermostat. I took it easy on the new engine while breaking it in.
Thus began the overheating problem. The temp gauge now hung out at about halfway between C and H when before it would ALWAYS stay well below the halfway mark no matter how hard I drove the truck( or how hot it was outside, think 103 degrees in Arkansas). Additionally the temp gauge would rise to just before H after about 20 mins at a highway speeds. Found out my Fan clutch was worn out and had that replaced.

Now I could drive a bit longer without the temp shooting up but the gauge still hung out at halfway and after driving hard would once again rise to about 3/4 or a tick higher between C and H. I had the thermostat taken out and of course the engine didn't overheat.

I had a thermostat straight from the manufacturer put in and bam! it seemed the issue was pretty much resolved. I took a drive on the highway for a couple hours and the temp stayed below halfway. I even bombed some big hills after just to make sure. I thought I was good until my long drive a couple days ago revealed the issues explained above. Thanks for any help guys! I have a feeling its something stupid easy but I'm just fed up dealing with these issues. I just want ole red back in action 100%.

ksti

So from what I read your motor is running "hotter" than normal, not overheating ( gauge pinned on hot, boiling over, loss of coolant) correct?
I'm assuming you replaced the water pump also.

Did you rebuild the motor because of a "problem" or just because of higher mileage?

Sustainobile

Correct. It hasn't overheated but the gauge did get close to H at one point during the long drive back to Washington. Also it will read out close to H if the engine is warmed up and I shut it off, then restart the engine. I dont remember off the top of my head if the water pump was replaced. There was a lot going on at the time. I had the engine rebuilt because during the last tune up I did, I had a mechanic check over the truck and somehow the spark plugs got stripped during the process. The plugs and the threads inside the engine were stripped. Additionally I had a compression test done and I had only 1 running at 100% the rest were super bad like 30% and the like. The engine did shake a lot and was misfiring. I was living out of my truck down there and I couldn't spend time to hash out all these problems so I had a rebuilt engine put in. No more shake.

ksti

Do you have records (receipt) for the rebuild?
That's something you need to know.
Look on receipt list of parts.
I'm going to assume a new water pump was put on as part of rebuild, but I have seen where it was not.

Sustainobile

Just went out and looked at the receipts. No new water pump.

ksti

That's pretty silly to rebuild a motor and not replace a important component like the water pump.
While I can't confirm it's a bad water pump, i still do suspect it's might be going bad.
Any leaking or coolant loss, (having to add coolant?)
I wonder what else they left out.

Sustainobile

Yeah... well do you know if the water pump would cause the coolant temp to read almost to H after the engine has been shut off and restarted? As stated before it cools down quickly after I get to moving. No leaking or coolant loss.
The only other thing I could think of would be the radiator maybe not having the proper amount of coils? its the same size as the old one

ksti

A water pump not functioning properly can cause this issue.
But like I said I cannot confirm it.
I would take it back to who ever rebuilt your motor.
If it's only been a couple of months, I would think they would at least check it for you NC.
Is their some kind of warranty?

Sustainobile

the was but I'm back in Washington now. All this was done in San Francisco unfortunately. I have been thinking about the water pump, maybe something with the temp sensor too? With everything else the thing that gets me is why it gets so hot after shutting off. I guess I don't really understand how an engine stays cool after shutting off. Something to do with residual coolant pressure?

Sustainobile

Ill do some examining and maybe replace the pump and post the results.

ksti

That's pretty normal for that to happen on a liquid cooled combustion engine.
There is no coolant/water flowing and the liquid heat soaks the block causing temperature to rise.

Sustainobile

I understand that but i dont remember it ever reading so hot upon restart. Yours doesnt do that right? I feel like i wouldve noticed if my temp was hot on restart.
Going to check the water pump and temp sensor tomorrow

azgold

Any update ?

Sustainobile

had the truck looked at. Im going to get a new water pump put in tuesday. In addition, my ac condenser is very clogged with years of debris and bugs so the mechanic said i could get alot more airflow to the engine if i got that replaced. It would be nice to have functioning ac as well. Will update as things progress

Sustainobile

Ok, sorry for the long delay in updating. Life... I just got the truck looked at by a trusted Toyota mechanic and he is saying that it is the fact that my AC condenser is clogged up blocking a lot of air from entering the engine bay. That was his explanation for it getting hotter than normal at highway speeds while going up hills and inclines in general. As far as the temp gauge reading 3/4 of the way hot on restarts goes, from what he has told me and through research, this is normal. I guess I just never really paid attention to the temp until I started having issues. It makes sense seeing as there is no electric fan to cool the engine after shutdown and the coolant sitting in there is soaking up the heat. Duh... Besides the condenser I have a number of other issues such as an inoperable knock sensor, need new shocks and leaking valve cover gasket and leaking oil cooler adapter. I still want to replace the water pump just because the old one is very old. I don't know if it's ever been replaced and I'm at 236k right now! I wish I had another vehicle to roll in since these issues take me well out of my comfort zone to fix myself not to mention I hardly have the time. The mechanic is going to give me a quote and I'm pretty sure it's going to be around 2k to do all the things... So, that's where I'm at right now y'all. I'll update as events unfold.

scope103

A "real" mechanic is almost always better than what you can find on the internet. Especially better than me. But here goes ...

Replacing the condensor won't make your A/C work; whatever is wrong with it (could be LOTS of things), bugs smashed into the condensor isn't it. You could use a pressure-washer (or equivalent to clean it), but once the fins get bent over a little bit it will be hard to restore full flow. Putting a new condensor in is only, oh, 5% of fixing the A/C. Something to keep in mind.

"Inoperable Knock sensor" can really only be determined by code 52. Do you have CEL on? Even then, it's very unlikely to be the knock sensor itself (they are VERY tough), but the pigtail. Still, a good mechanic is likely to say "If I'm going to charge him to dig all the way in to replace the pigtail, he won't notice another $75 for a new sensor." Peace of mind.

Leaking head gaskets are common (and almost always caused by an inadequate installation). But they are an easy fix if you're going all the way to the knock sensor. The oil cooler adapter is an easy fix and should be done. Oil is supposed to be inside the engine, not on the driveway.

If you want to replace the water pump, go ahead, but I'd be surprised if that's an issue. There isn't much to a water pump; if they aren't leaking, they're fine. You need to remove the timing belt to get to it, so usually you'd replace the belt, but yours may be nearly-new.

Just be sure you know what you're buying, and don't be afraid to ask questions. All mechanics love customers who learn everything from the internet. ;^)

Sustainobile

I've been without AC for a long time so replacing the condenser would be just to let more/better airflow to the radiator. He put a piece of paper up to it and it wasn't sucking it like the radiator does. I've also read that the condenser is too far from the fan to suck a piece of paper so I don't really know what to think. But if I can just pressure wash the junk out of it that would be way easier. I'm not particularly trying to fix the A/C, just get more airflow. I'm also thinking of how I could blast the junk out of the condenser without getting debris in the radiator fins... I suppose I could just take the condenser out but I'd still have to pay someone to recover the refrigerant and all that.

As far as the knock sensor goes, I should have specified that there is a CEL on and has been for quite some time. It came on last year and was intermittent at first for a while. Now it comes on pretty much right after I shift to first and start moving. The timing was checked and is off so he said that could possibly be a contributing factor. Of course the knock sensor has to be deep in the engine to get to. I've done a valve cover gasket before on a ford contour so I may try to DIY that job. I'll look at my repair manual and see about doing the oil cooler adapter DIY as well.

The water pump is going to be pain in the butt, if it's going to gouge me any worse than I'm anticipating then I may forgo replacing it. Unless the opportunity arises.

ewong

Well, there is a way to read the code that is stored by the CEL

We'll need to know what THAT problem(s) is

GeoRoss

Based on what you said I would also look at the fan clutch.